Study Plans and Custom Sessions are the two main ways you can build a Qbank session, depending on how you prefer to study.
The blocks in Study Plans are pre-made exam blocks broken down by system. These plans are usually suitable if you have more study time or prefer to work through subject areas. You can find all the question blocks in the Study plan section on the left sidebar:
Through Custom Session you can create your own blocks of random questions for each exam and further filter as you want. This can be a more flexible way of setting up your Qbank session, and a better option if you are closer to exam time. You can check how to create your Custom Session here.