How to correctly install the site on the server (Flask)?

Question

Flask

Good afternoon, I made a website, and I need to arrange a rite of installation on the server, I thought to do it all through sessions, but alas, it didn’t work out. More specifically, you need to design one router so that it is the first when you first enter the site, or until some variable becomes positive, let's say the variable , so who did something like that, give advice about routing, etc.? Add. Or connect a database and use it to manipulate sessions? What is the best way to handle this whole thing? Installed = True