Earlier quoted context omitted.
Documentation and ease of setup have long been the biggest weaknesses of Tor. The browser is easy but setting up a server or any of the infrastructure isn't. The first time you setup a server or a relay expect it to take half a day to a full weekend.
The Tor community improved a lot the Tor Relay Guide in the last two years. Actually now you can easily setup a relay following the instructions: https://community.torproject.org/relay/setup/ And if you're an Ansible user, you will enjoy Nusenu's ansible-relayor: https://github.com/nusenu/ansible-relayor
I forgot why exactly I didn't use ansible-relayor last time I setup relays but I had a reason. I'll try to use it next time I deploy a batch of relays.