SOLO is the libraries' online catalogue. You can find maps here as well as books, journals and other materials. But if you are just looking for maps, you will find the Map Search useful.
The Map search can be accessed here, or by following the link from SOLO front page.
A simple search here will just find maps:
There's also an Advanced Search for maps; click here or follow the link from the Map Search page which you might find useful if you're not finding what you want with a simple search. See the next page of this guide for more detailed guidance.
If you haven't used SOLO before, you may find it helpful to consult the general SOLO guide first.