Problem creating new users in playground for AZ-104 course

I’m learning AZ-104,but while creating new user in playground for practice I have only access of creating external users . This my first issue.Secondly after giving external users invitaion I’m unable to find that within all users

In general, we don’t allow our playground accounts to create users; this is a security issue. From our FAQ:

When you first log into a playground, you start with an initial user, usually something like kk_labs_user_XX. This has a set of permissions. In the playgrounds where you can create additional IAM resources, those resources must have specific names and cannot be granted any higher privilege than the user you log in as.