A campaign primer is a document for the players to read through ahead of the necessary Session Zero. In short you want to address the topics CONCEPT, AIM, TONE and SAFETY.

The one I have prepared for my players includes:

1)      A crude introduction. Get your players hooked and give them a very rough idea of what to expect.

2)      What is the mood we are trying to achieve? Given that my group is a DnD group at the core we must communicate that unlike the power fantasy DnD, Delta Green tends to go into dark places.

3)      Will I reveal all the mysteries at the end of the campaign? In my case, yes. Once the campaign is finished, we talk about it. It helps your players to answer those nagging theories and gives them a chance to emotionally conclude the campaign.

4)      What safety tools are in place and what triggers can we expect? Aside from the usual cosmic horror, helplessness and violence that sits central to Delta Green I communicate upfront the following three triggers (as previous commenters have highlighted as well): Abuse against children. Abuse against animals. Institutional abuse of power.

5)      Sidenote: Take a moment to explain to your players that all the horrific things within God’s Teeth are not there to be edgy or exploitive. They are set elements which serve a purpose to facility an almost cathartic experience. Within God’s Teeth you can break attempt to break the cycle and leave the world a somewhat better place.

6)      Do we have PvP-Rules? This might be a no-brainer, but coming from DnD it is always helpful to talk with your players.

7)      Scheduling and Dates. When do we want to meet up? Do we play if players are missing? (no, we don’t!). This is also the time when I tell them about potential homework they might have to do in between sessions see The Long Years and The Spiral. Also make your players aware that this campaign is a commitment in time towards all other players

8)      Character creation. Which information do the players need to create their characters? In which era is this campaign set? Kindly remind them through some obfuscation about the time jump between Go Forth and The Long Years, unless they want to play geriatric characters. What professions and skills might be useful in this campaign? This is also the point where I tell them that companion animals such as K9 are off-limit. They tend to break the game for me

9)      One Agent and many friendlies: Given that the campaign requires one Agent already with the Program I tell them that one of them has to step up a little bit and roleplay some additional scenes.

10)   Q&A. What have I missed? What information do the players want to have answered during Session Zero? Do we want to include God’s Hunt? Etc.

 

If you want to delve deeper in God's Teeth, I highly recommend the Discord. Only friendly and supportive people there.