No one is laughing at you Lisa, we've all been there before. The joys of learning mechanics on a truck mount. Boy can I relate.
To find out what size blower you have, measure the diameter of the gear box and the width between the gears, ie the length of the blower lobes. You may even find a name plate on the blower.
To measure vacuum, you should have a vac guage on the machine. If its not working correctly, check the small hose coming off the guage which should run to a point between the blower and the recovery tank. Make sure its not crimped or cut. Replace the hose/and or the guage if necessary.
We're big on pictures here, open a photobucket.com account, take lots of pictures, copy the "img" url, and post it on here.