Its time to learn to set the depth of your cut, something you should always do.
First, unplug the saw. (I never do this, but it is good advice, ignore it at your own risk)
Behind the saw there is a lever beside the handle, flip it up.
The metal plate on the saw will now move up and down.
Pull the balde gaurd back, and set the plate on your wood, with the blade hanging off the side.
Move the saw so that the plate is still on the wood, and the bottom of the blade is just slightly lower than the board you are going to cut.
Push the lever down just enough to hold the plate from moving. A lot of novices make the mistake of pushing this lever down as hard as they can, this will eventially ruin the depth of cut so don't do it.
plug your saw in and cut away. Be careful not to cut the cord. Sounds stupid, but half the expirenced carpenders cut a cord at least once in the 9 months I was in the buisness. (The idiots managed to do it up to 3 times in a week) Also don't cut yourself, this is a dangerous tool.
It isn't hard, but you should know how to do it. If this doesn't make sense, either read the manual or pay someone else to do it. There are some people who shouldn't own tools if you are one of them it is better to admit it and spend time doing something you can do (perhaps that I shouldn't do...) instead.