How and where to start building web api backend?

Hello,

Currently I have almost fully coded frontend and would like to create backend api endpoints. I started to learn go, finished one udemy course that covers language fundamentals.

My question is: where to find course/material to start building whole backend? I found many tutorials regarding api creation, but I struggle to find tutorials for complete backend architecture, folder structure, ORM, middleware, hosting, CI/CD and other stuff that I don't even know (I am working as FE dev and have little knowledge about backend).