Question pools are the key to making groups of questions that can be reused. Random blocks give you an easy way of limiting the display of questions on a test to just a selected pool or pools. Question sets enable you to reuse questions from anywhere in your course, not just from pools.
When using random blocks and question sets, notice that you will determine the number of points assigned to each question in the block or set. If you want to set the number of points for each question individually, you should add the question individually, and not as part of a block or set.
In the next chapter, you'll learn about working with groups. You will see how to assign students to groups, grade them as a group, and communicate with them as a group.