To query staff do the following.
Go to Reports, Query, Generic.
By Choose Table (1) select Staff. Choose Field (2) Select Period or what field you want to query on. Now choose the period (3). Click on Add (4). You can repeat steps 2,3 and 4 as many times as needed. (For example to query by location, class etc.).
After you are done adding the criteria choose Parent Query (5) and click on Include (6).