Can anyone help me please? Thread

Dear EveryoneI am new to this site and I find it very friendly so I thought I might ask for a little help, I have bought the Quake Collection from Steam and want to play the mission packs in Epison or Darkplaces because the graphics are terrible, I am very confused with how to do this, does anyone know and can explain it to me as a beginner, I am quite good with computers but this gaming is a little bit new and complex for me, any comment or help at all would be really appreciated.Thanks for listeningWith Respect to you allAlex