This is a recreation of the classic infection gamemode, where one player gets randomly infected at the beginning of the round and has to infect all others. In order to win as a human, you need to survive for a given amount of time and then find and go to a designated extraction zone.
You can find a pre-bundled version of this mod here. You will also need the battlerecorder mod alongside it for this to work.
This mod currently only supports one map, so make sure you have this in your MapList.txt:
XP4_Quake TeamDeathMatchC0 2
You can configure various attributes of this mod by editing the ext/Server/config.lua file.
If you want to build this mod from source the only thing you'll need to do is package the UI. You can do this by running vuicc.exe and pointing it to the ui directory of this mod:
vuicc.exe C:\path\to\infection\ui ui.vuic`
Then place the produced ui.vuic file inside the mod folder and you're good to go.