Piece o'cake. Undo the two phillips screws and lift the covers off. Spend the next 40 minutes searching for the screws that have **cked off under the workbench.
Notorious for the cables getting stuck in the drum (I have NEVER changed them without resorting to bad swears) and a needle pointed pick is essential.
As Brucey said, RH shifter in 7, LH in 1. Don't forget to bottom the adjusters before fitting the new cable then stretch/settle the inners and outers, undo the pinch bolts and manually retension the cables before attempting the indexing.