I do not seem to be able to get the Rocket Chat running. Correctly. Some can help me to find a step by step instructions, please? with my 60+yrs I seem to be lost here a little.
I installed it on my site at xsimracing com / XSIM/ but this Rocket Chat does not work.

RocketChat requires to be installed at the root level.  First determine what your OS is on the server and then go to rocket.chat and you can find detailed instructions for your OS on how to install it.  You also need to set up a reverse proxy on your webserver; that can be tricky sometimes.

I do not seem to be able to get the Rocket Chat running. Correctly. Some can help me to find a step by step instructions, please? with my 60+yrs I seem to be lost here a little.
I installed it on my site at xsimracing com / XSIM/ but this Rocket Chat does not work.

I don't like RocketChat; it works and then you do an upgrade and it won't bring in the avatars.  What is needed is a native chat application but no one seems to be interested in writing one.  It just needs to be a simple chat; maybe with webRTC audio/video chat, but applications like RocketChat are overkilled.