Back-office or Front-office - both are needed, but what should be created (written) first?

Question

CMS

I want to write a website myself. No CMS. So, I will write the engine myself too.
Tell me, please, where to start creating a site: from the back-office or from the front-office?

Answer 1

What for? Take a framework and make a CMS based on it for yourself.
If it’s fundamentally yourself, then you need to start with the back-end, since having made the front-end, let’s say some kind of form, or ajax, where will you send the request?

Answer 2

First, work through and at least briefly describe the functionality of your application, select entities, modules, divide into Front office and Back office.
Then it will become clear what needs to be implemented first.