1.We already have SSO configured at BTP. We are trying to add subaccount, what are the credentials to be given in subaccount user and password and how to get the credentials?
2.We have cloud connector setup and BTP subaccount is added. Later, We have registered SSO for BTP subaccount.Any changes to be done at cloud connector setup after enabling SSO for BTP?
You get it, when you register your BTP subscription. (Which probably the account manager of your company has done, or will have to do.)
A free trial account can be obtained as follows: Get a Free Account on SAP BTP Trial | SAP Tutorials