I am learning, and I need help..

There's two ways (that I know of atleast) that people slice. I slice using the marquee tool and cut and paste every piece I need/want and save them individually. Others use the slice tool. When you're done using the slice tool go to File>Save for Web, or something like that (I can't remember without opening PS), choose your format and settings, and you're basically good to go. If you want, PS creates (very horrid) code for you. As bad as it is, it saves you from creating a new file if you're really lazy :P. After all that, you're basically ready to start coding.

I found when I first started slicing/coding that I had to go back to the original file A LOT and re-slice a lot of pieces, it may have been just me, but be prepared to do it anywho.

Good Luck!