Tim.
This may not be the quickest way but I do the following...
Select 'Browse Sites' (in the red banner at the top of the page).
Select the appropriate geographical areas as required until you get down to the county you want (ie. UK, England, Southern England and Somerset)
Select 'Add ' from the middle grey banner which gives you a drop down menu where you can then select 'Add Site'.
You then fill in all the details as required and submit it to the Ed's for approval.

:)