Credit to next_ghost
Prerequisites for hosting your own server.
A: ability to read
B: clicking mouse and typing on the keyboard
C: knowing the difference between directory and file
D : knowing why the program stops working when you move some important file into wrong directory - 75% of people I tell to give up utterly fail here [you fail here]
E: knowing how to write a plain text configuration file (no specific configuration knowledge needed) - that's another 15% down
F: being able to find out what to type in the configuration file to make the program do what you want - 5% down
G: command line basics [or here]
H: knowing how a server works in general - remaining 5% down [or here]
I: ability to solve common errors
J: networking basics - people who get beyond this point qualify to run their own server
K: ability to solve weird errors
L: ability to build your own server
Easiest way is to go into an existing TremX server, make sure cl_allowDownload 1, and download the pk3s automatically. Then, open your <trem user> folder, and the tremx folder should be there. Using that folder name, use it as the fs_game name, i.e +set fs_game TremX using the command I showed you earlier.