linking existing mailbox to a new user

Hi all,

i have set a test environment with a DC-MBX servers. I made it same as my prod, the difference is that domain name of both are different. i imported users to test env from prod. restored prod exchange mailbox databases to test environments and mounted them.
i see that Get-MailboxStatistics command show me the users and item counts. but when i look in Exchange console in Recipient configuration/Mailbox there are no users, as this is fresh new test environment. when i create a new mailbox it does not see the mailbox from restored database, it creates new mailbox.
my questions:
1- how can i get mailboxes from restored database which are now mounted and healthy?
2- what should i do so that when i open outlook for a specific user i get his emails/items from restored database?

thanks in advance