If you haven't already, make a note of your Liverpool Uni Student ID number (on any ack letter) you will need it to sign into the Liv Uni portal and to apply for accommodation.
Accommodation is allocated on a first applied first served basis. It normally opens around Jan/Feb time so keep an eye out. You prob wont be told by the med school for some time after it opens so watch the Liv accom threads elsewhere on TSR.
You do not have to wait until you have received an offer to apply for accommodation, can do it when it opens as long as you have received an invitation to interview. So do it as soon as it opens, nothing to lose (and no cost to pay on application).
The accommodation in Crown Place in particular (rather than in the residential village) is often over subscribed after the first weekend. So be extra prompt if you want that one or Vine court etc.
Apply even if you have not been to an offer day and have no idea what you want (but do a bit of online research first!). You will have your name on the list and if you have a burning desire to change your choices later on you can.
Also hunt out your qualifications certificates (GCSE/AS/A) etc as you may need to provide copies before interview. Liv do look at your administration of your application, so be prompt. The FAQ on the website as well as the Departmental Supplement should be your bible. Read last years thread for indication of timings etc and potential things to do.
Lastly, do make sure you have set a filter on your email to pick out anything from Liverpool / Liv (esp if you have Gmail) as quite often stuff seems to end up in the spam folder.
Good luck !