I was in your shoes 4 weeks ago, I didn't know squat! Lol...just study threads and other resources to fully understand the meaning of what each number represents for each sensor, from there you will have a better understanding on tuning the car for what it needs. More fuel less fuel , more or less timing ...all in relationship with the desired level of boost.
it is the most or one of the most inportant tool to have when tunning these gns it tells you what the motor is doing at all times .if its running rich or lean tells you where your tps is millivolts .era codes ect. then you would need an adjustable regulater.and the guages