The single biggest newbie mistake is too much blade exposed. In a nutshell you need to remove your blade holder from the machine and manually cut across a scrap and determine that your blade is out far enough to cut through the vinyl but not long enough that it can cut through the backing. You may have seen MZ Skeeter's posts around the forum because she has posted literally thousands of times on it.
Blade depth is the first and most important set-up and all the other settings are dependent on having the correct blade depth (blade exposure) setting.
