Yeeah, there are too many things to play, great games everywhere with hours and hours of content. I know that dedicating time to another game is not easy when you have so many to play.
The previous server used "plugins", basically they were modifications but they are only installed on the server and the players can see them and use them without having to install them manually. Then there are the "mods" which are modifications that must be installed both on the server and in the client game in order to work. It is a bit more tedious to install everything, but it is not that complicated. If you need help or have any other questions let me know.
