I’m setting up sources in Airbyte using their API and need to specify the sourceDefinitionId. How can I retrieve these IDs? Or do i even need it?

I am sending a POST request to this endpoint: /api/v1/sources/create with this body:
{ "sourceDefinitionId": "some ID", "workspace_id" : "my ID", "configuration": { "sourceType": "facebook-marketing", "account_ids": ["my account ID"], "access_token": "my token" } }

I have tried to copy some sourceDefinitionIds from Github but they didnt work, also in the docs i could not find something that gave me a clear answer.