Yeah, they do not make this intuitively obvious.

If you insert a putty knife or screw drive in the gap between the front and the top at the ends you should be able to release some clips that will allow you to flip the top upward.

Now you can take off the front, which should be held with just a couple of screws. You will have to unhook the door switch, so mark how the wires go so you can put it back together.

At the back you will see a small access panel. Take it off and you can reach the belt tensioner and motor pulley.

You should now be set to go, just take your time, do it slowly and don't get frustrated (advice so good I rarely take it myself)