Welcome to VMware communities . I understand that you are trying to deploy Skyline and you are getting an error in the step where the support entitlement gets associated.
We do not have to perform any additional steps to associate support entitlement .
We have checked the EA for details and found that you have Basic support entitlement. Skyline is currently only offered for Production and Premier support entitlements only.
Please do let us know if you have any other support entitlements.