How to get and setup Project Members in API-V8

Hello,
I try to get some Information over the API, like Project Members or similar.
I saw that you can add members more or less over the “Resources” tab, but I cant see a solution to receive these Information over the API.
so my Question is more:
“How to register Project Member”- or- “when are people registered as Project Members”
and " How to receive these Information over JSON API"

Thank you and Greetings
Shiranya