You don't need to run the queries, but you should have a feel for what is possible. This will help in reaching decisions faster when you must compose a query quickly. Studying Espresso can take a few hours and is best done while not under pressure to deliver results. The Help file explains each phrase. Whichever way you learn Espresso, we know it will be very useful.
Views take very little storage.
A user with full write resource permissions is very unlikely to consume more than 1MB of database space. DBsurfer users have no control over that. However, you can redesign this arrangement easily. Say you need to find out regularly the average grades for a particular course description. The description is in the Course entity, the grades in the Grade entity.