How to start developing a project?

Question

PHP

I have an idea to implement one project as a practice. At the moment I can create a simple system, with page listing and data fetching from MySQL.
I decided to make a real project, which in the future I want to immediately launch, and if it takes off, then support and develop it.
The question arose: where to start the implementation of such a project, if there are layouts, page prototypes, but there is no knowledge of where the implementation of the system begins. More precisely: with what functionality should you start? Suppose there is a registration on the site (further functionality will be tied to it, because this is not a news site) - is it worth implementing it at the beginning, and then implementing internal sections / modules?
If registration is the first step, is it worth finishing all the components that are associated with the user card to the end? To fully work both the registration itself (cookies, sessions, security), and the user profile, as well as the user search (I remind you of my service).
For example: foundation pit, foundation, basement, floors, electrics \ sewerage, installation of double-glazed windows and cosmetic repairs (roughly speaking) - these are all stages, and they are all interconnected. So where to start? If we take the foundation pit for the php framework, then what should be the foundation?
Where is it desirable to read specifically on the subject, and not abstractly? Prompt useful materials. Thank you in advance!

Answer 1

you should start with tests, with tests ...

Answer 2

Start by implementing an MVP. What is it - ask Google.

Answer 3

Start by testing a hypothesis that solves your particular problem.
And if just for practice, then what's the difference on what to write and how to write?

Answer 4

From the choice of a framework, if you write from scratch, the enthusiasm will quickly fade.