Enter your email address. Each email box can have multiple addresses configured for it on the server -
but you will have to choose one of them to enter here.

You only need to check each mailbox once to receive mail from it.
You do NOT need to set up one account for each address a mailbox has unless you want to be able to send mail using the different addresses. In this case you set up another account with the alternate email address (and name if desired) but you need to set it NOT to be checked when receiving mail.