I am not completely sure what your question is actually asking, but I will interpret it as requesting recommended best practices for starting a new business from scratch. Plus, given the style of your question, I will assume you are talking about a technology and/or software company. There are a number of tools and templates that exist to help individuals/teams accelerate their progress, and I will try and cover the most effective.
Starting a (successful) business requires many factors to be in place in order for it to work. In the ideas stage (i.e. when you are formulating the business in your head), the most significant of these being value proposition and revenue streams. That is to say: what is the product and/or service the business would provide, why is it worth anything (and to whom), and how will you find ways of getting your customers’ money out of their wallet and into your pocket?
There are many other aspects that are important (more on that a little later), but these are key questions that form the basis of your business plan - what, why, whom, and how? To a lesser extent you must also include when and where as well.
A good starting point for this thought exercise is the Business Model Canvas. It is an excellent way of mapping key factors, questions and decisions into a practical set of actions, which will help you judge a business idea’s viability. A business plan takes the results of this exercise to the next level.
You can think of a business plan as being your way of trying to convince others that your business venture is a good idea. In it you must highlight everything about the business that will make it successful, the risks and problems you will encounter (and how you will overcome them), and the potential rewards that it will bring. Personally, I like to take it to a higher standard: use your business plan as a means to convince yourself to invest in your own company (whether that is with time, effort or treasure). Write it with enthusiasm, but read it dispassionately, and ask yourself: “If someone else were trying to convince me to mortgage my house, and take my children’s college fund, to invest in this business, what would I expect them to show me?”
As far as templates go, archetypical business plan structures are well documented.
Now… assuming you have conducted your research, found a niche in the market, determined how this niche can be filled, calculated the cost of filling the niche, weighed up the risks/assumptions/issues/dependencies (or strengths/weaknesses/opportunities/threats), and created a sufficient number of financial/marketing/hiring/contingency plans, then you are now in a position to start building your company. Again, I am assuming we are in the technology and/or software space here.
In general, there are four main areas that need to be covered when starting a new venture: operations, product, technology, and marketing. A individual person can (theoretically) do all four, but that is not sustainable for more than a few months. The attention and skills necessary in each area are quite specific and require different characters and experience to do properly. Over time, an entrepreneur should look to cover these core areas with specialists capable of leading each of them, while still collaborating with each other. Eventually, teams need to be built around these core leaders, who will spearhead their own initiatives for the company.
Covering each in turn:
Operations - this encompasses the day-to-day running of the company (e.g. handling paperwork and registrations, managing compliance, ensuring bills get paid, managing contracts, etc.); in the early days they may also take on aspects of finance control, legal, project management, and human resourcing until a full-time people can be hired for those roles.
Product - this area is about acting as a proxy to the customer (i.e. building and understanding the value proposition of the product/service that will define the company’s viability); usually handled by someone with Product Management/Ownership experience.
Technology - this covers everything from IT infrastructure to designing and building the product/service; this should be handled by an experienced technical lead, capable of working with Product to design and plan the strategic roadmap, system architecture, and delivery timeline (they will also be the person to select the technology stack/stacks and build out the development team).
Marketing - this area is critical for bringing attention to your company and will work closely with Product to win customers and credibility; Marketing is also crucial for building a corporate profile in the event that you need to seek investment or strategic partnerships, and helping with market research in the early stages.
When discussing solution provisioning, we then focus on Product and Technology. In the earliest stages, Product and Technology must work together in order to determine the what, why and how of the company value proposition. Product will likely work with Marketing to gain an holistic understanding of the target market and the underlying opportunities. Technology should also perform market research from the technical perspective, then compare and contrast the findings with Product. With any luck Product and Technology will have drawn similar conclusions as to what opportunities are viable (i.e. Is there a market need? Do existing solutions already exist and - if so - how do they compare? Can we provide a better/cheaper/more effective solution in a cost-efficient way in the time allowed? What are the threats/risks/issues that could derail the business and how can we mitigate them - if at all? etc.).
The key challenges here for Technology are to:
Determine if a solution is possible (and if it can eventually be delivered) before any more money is spent (if the business is destined to fail, better that you find out as early as possible); and
Design and plan a technical roadmap for product delivery (short-, medium- and long-term), along with alternative paths and contingency plans.
It will likely also be a hands-on role for the person accountable for Technology, up to (and including) the point when a development team is built around that person’s leadership. Similarly, this same style of practice can be applied to the more granular level of the development lifecycle, just more iteratively and with higher velocity.
There are many ways of planning and executing a technology roadmap (too many to list here). Most are built around corporate and marketing voodoo, selling the idea that anyone can build a great technology product if they follow a magic recipe. Be wary of such thinking and try to find someone with a track record of delivering high-quality results using their own judgement and experience. The software industry has struggled to meet its own expectations for many years and that is unlikely to change any time soon. If I had to pick a few methodologies to elevate above all others, I would advocate the techniques of Volatility-based Decomposition and Anti-fragile Development to be the most effective at delivering high-quality products and honest timelines. But that is a separate discussion for a different question…