The Studio 32 is an analog mixer, which you can use for a variety of things. To learn how to use it I suggest you read the manual (go to alesis.com if you don't have one and search through their product documentation for a downloadable manual).
To interface with Pro Tools or any other digital recorder you will need an interface on your computer that can input an analog signal. Any soundcard with a line input is capable of inputting 2 channels of analog audio that becomes digitized once it enters the computer (there are numerous choices and different levels of quality for soundcards, and it is recommended that you check out a card designed specifically for audio recording like the M-Audio Audiophile or the Echo Mia, for instance, as entry level cards).
A Pro Tools setup is a slightly different animal than you would deal with if you bought another recording program (like Cubase or Sonar). Pro Tools uses its own hardware for the interface card (for the Digi001 system), the MBox uses USB to interface with a PC, and the Digi002 uses Firewire. Any of these can accept inputs from an analog source like your mixer, with various numbers of inputs.
I hope this gets you started. Your question reveals that you really have a lot to learn, but don't give up. Just keep on studying and asking questions.
Darryl.....