Your owner's manual will tell you how to change the needle. Generally, the needle is held in the bar with a screw. Look at how the broken needle is positioned before you unscrew it. Unscrew the broken needle, slide the new needle up into the hole, and rescrew. Needles break for several reason--you pulled the fabric behind the needle faster than the machine was feeding it or you hit something are the 2 most common. Check the owner's manual. It should have a trouble shooting section that will talk about needles breaking. Did you buy your machine from a dealer? Dealers usually have after sale services such as operating lessons that walk you through things like threading the machine, winding the bobbin, and changing the needle. If you don't have the manual to your machine, I urge you to contact your local dealer and order one. It has all kinds of information in it from identifying the parts of your machine, how to sew the various stitches, maintaining the machine (oiling and cleaning), change the needle and light bulb.