Dial the access number, enter your six-digit PIN at the prompt, and Email2Phone tells you how many new and saved messages you have and drops you into the same menu you get when it calls you. Access numbers in the US, Canada and the UK are on the contact page, and dialling in is free on every plan, including the trial.
Saving a message for later. Press 8 on anything you will want again and it is in the saved folder next time you dial in; main-menu 3 opens that folder. Messages that were never acknowledged after the fifth callback are filed in Message History in your online account, where you can read them.
Your PIN is generated when you complete signup and appears in your account profile; it is also shown when you log in. Write it down.
Connected mailboxes. Mailboxes you have connected are fetched live when you dial in and never ring the phone; main-menu 5 says which one you are in and 6 moves to the next. The full keypad is one article over.