Doing a Level Search...

1. Go into the Catalogue (TTPlus)
2. Type in a few letters of the Level you would like to find items from
3. Click the Level button
4. Click one of the Series in the list that appears (or hold down Ctrl and click several in the list) then click Ok

Play around with the results until you end up printing a list of the items or looking at the details screen to see if the item is available or not

See Using the Results Screen (Resource Lists) for more details about manipulating the list of resources that appears as a result of your search...