If you are needing some more explanation as to the material we covered in class – or simply some examples worked through in a methodical way. Here is a link to aShiffman textbook called Learning Processing. It has allot of worked answers and we have covered some of the key concepts in Chapters (1-5). Particularly take a look at chapter 4 on variable, take a look if you need help.
The recommended textbook is the top one here. It also has allot of simple examples. It is in open reserve if you want to study from it or read it for backup.