Kelly is right. At minimum you need a points calculator of some kind, the points range information. A bonus is the activity slider, I put that on my must have list. You can get in your first meeting a booklet on the ins and outs of the program, the points calculator and some points listings (which you already have in the companion). It's week 3 or 4 when you get the activity calculator/slider.
You should get a journal of some kind. Each week at the meeting you receive a free tracker for the week to track your points. Or you can buy a 12 week one. I made my own in excel based on the WW one when I did it on my own.
For the Flex plan there is a points target for your weight that decreases as your weight decreases as well as 35 flex points that everyone recieves no matter what thier weight to be used throughout the week as you see fit. Exercise allows you extra points, which are caluclated by intensity duration and weight. If you ahve a newer companion book you could try CORE. In the front you will find a list of core foods and throughout the book anything check marked is core. The idea is to eat anything off the core list when you are hungry and stop eating when you feel satisfied (not stuffed or full but satisfied). You do not track points with Core except the 35 WPA (same as the 35 for flex). You use these when you eat a non core food. You can also earn activity points with core.
The magazine is nice, but really not that helpful. You can read free success stories online, get recipes here or even a few on WW online for free. Most of the information I have found in the magazine is stuff that you can find most anywhere these days...walk 10,000 steps a day, chocolate has some health bennefits. Stuff you hear on the nighly news. But I get the magazine and do enjoy it, it's just not a must have.
I highly recommend attending one meeting at least. Or finding a friend with an old slider. If your mom is a member she can buy an extra one, they are like $4 where I live.
Best of luck

It's a great program!!