How to view 3 identities on the one account

[nicb137]

Hi,

I had set up my account so that I could see 3 different identities in my list of folders.  I thought I didn't need that, so deleted them, and now would like to re-instate them but can't see how to do it, or remember what I did last time.

I've got 3 different e-mail addresses for my domain, and want to be able to see mail from all 3 when I log into my main account.

Can anyone help please?
Thanks very much