What is critical information for you may not be as critical for someone else. Some people use this container to host a wordpress site, no reverse proxy needed. Some only reverse proxy. Some host a forum, some do all. Some run it on unraid, some on debian, some on rpi, some use portainer, some use docker compose and some use bash.
You keep asking for step by step instructions but given the vast number of scenarios this container can be used in and for, and the vast number of apps/guis you can reverse proxy, it is not possible to cater to all (not even the majority) users with a step by step guide.
"Everything" in that readme is critical information. It is all up front and center. We are of the belief that we should teach folks how to use something and provide the tools, so they can adapt it to their needs rather than spoonfeed them some information and expect them to copy paste. Teach a man to fish and all.
You already followed existing guides (by others) and weren't satisfied. You won't be satisfied with a guide unless it was written specifically for you, with your software and hardware environment in mind and with the exact apps you want to reverse proxy.
I suggest you contact the authors of those guides and videos with your requests.
With regards to your redirect issue, it may be browser caching of 301 redirects. Try a different browser/machine and if it works, clear the cache of the first browser.