Check Availability allows you to search for possible venues to hold your event. 

On the left side of the page there is a date listing.  Use the front or back arrows to select the date of your intended event.

On the right side of the page click on Filter if you wish to narrow your search to a specific building or room type.  Click Apply when you have filtered your options to those meeting the needs of your event.

     The C column shows the capacity of the listed room.
Once the selected filter has been applied and the screen has refreshed, times blocked in blue are already booked.  Hovering over those blocks with the cursor will show a summary of the event reservation for that space and time.