It's not a new set up. We have Fargate tasks running already and the roles set up.
I passed along the links for the roles and they said "the service-linked roles and task execution roles are more about the permissions that the containers themselves need to have." So again, that's all set up.
We're trying to create a new user, whose credentials can be used in the ECStask and s3 blocks, that has the minimum permissions required. Our Eng team asked me to find our the specific permission required for that user. My understanding of AWS permissions is not great so apologies if i'm not following or asking the question correctly.