Installation Link for Custom APP with Golang

Hello,

I am brand new in APP Development for shopify.

As a golang developer I would like to develop shopify apps running with golang.

However I have no idea how I might achieve this when providing a custom app by an installation link.

I know that I need to configure an app url and an redirect url. But what pages are expected here ?
Do I need to develop a frontend for that and what should this frontend do to enable the client to install my app ?

I really have no idea how to make this work and looking for some help.

Moreover I am wondering when it is recommended to install an app over an installation link the client needs to visit or to install it directly in the clients shopify account ?