QCDE is a Doom II mod, not a Quake Champions mod. The official package bundles the Q-Zandronum engine and a free IWAD — no Doom II purchase required: Windows · Linux.
Unpack the archive and run the bundled Q-Zandronum. Our server runs QCDE v3.1 with freedoom2.wad. Project home: qcde.net · mod page: ModDB.
Launch Q-Zandronum with QCDE loaded, then use the in-game server browser or the included Doomseeker:
qcdoom.sonofasam.com:10666
qcdoom.sonofasam.com:10666
No password required.