I don't know what kind of bike you've got, but the procedure is about the same on most models. On my Dyna, there is a brace that bolts to both mufflers. Four bolts hold it on. I think they are 1/2", but I could be wrong. There is also a clamp that holds each muffler on the header pipe. Look down near the passenger pegs and you'll see them. Just loosen these two nuts and pull the mufflers off. Sometimes they can be a pain to get off, but squirt some WD-40 on them and wriggle them back and forth and they'll eventually come off.
Look in the dictionary for the opposite of "mechanically-inclined" and you will see a picture of me. I put my slip-ons on about a half hour. Way too simple. Fear not.