Go to the youtubes and search for thargoid base. I'm at work so I can't post links, but we've found a base of theirs!!!
View from orbit : 16:15 Door opens : 20:29 First time is see the Thargoid Machine : 22:48 Eggs being fertilised : 30:28 The first time I realise I need 3 things : 32:00 Then the first one goes into place : 36:00 First time I lay eyes on the Unknown Link : 1:19:38 Moment I realise I just found an Unknown Link : 1:22:25 Unknown Link 1:24:45 I need an Unknown Probe : 1:44:14 Unknown Probe Arrives : 2:56:00 We enter the cave together : 2:58:30 Whoops, man down, SilentStalker locked outside : 2:59:10 I go get SilentStalker : 3:00:10 We Activate The Machine : 3:02:00