Sign in with the account that owns the Business subscription and open Your team. The seat summary shows the purchased Standard and Premium seats and the billing interval when the team service is available.
The roster shows assigned, pending, expired and unassigned seats. If the team cannot load, use Try again and check that you are signed in to the correct account.
Team access and features depend on the subscription and backend configuration; a team seat does not automatically provide access to another person's browser-local conversations.