It sort of depends on how the testbank is set up. In a published testbank, you may see one or more descriptors printed below each question.  If your testbank utilizes one of the descriptor fields to list keywords, you can use the "Filter testbank" option on the Tools menu to select the keywords you want. Then the filter will show you only the questions that have those keywords assigned and you can pick your test questions from them.

If the testbank has no keyword descriptors, the only other option (not the best) is to use the Find and Replace option on the Edit menu, but this option is only available if you have the testbank open for editing and would require more work because you'd have to make a note of each question ID as it is found by the search, then locate these questions later as you build a test.