Where to begin?

First lets start with getting the bot into the server although I assume you have already done that/know how to do that, if not here is what to do.

Firstly click this link, after that the instructions are extremely clear to follow, after this you shouldn't have a problem continuing by yourself after this.

What is Fatal-bot's prefix?

Fatal no longer supports prefixes, instead, use slash commands, all prefixes were depricated since 08/08/2022