There really isn't much you need to mark for a direct swap such as this. If you think you can tackle the job yourself then have at it. You can use a bow press to get slack in the rigging or just turn the limb bolts out till the string goes slack. Slip the string off, use a small screwdiver to pop one of the E-clips off the axle, then either push or tap the axle out far enough to get the idler out. Put the new idler in and push the axle through it, replace the washer, and push or tap the axle the whole way back through the limb forks. Put the E-Clip back on, slip the string back on the wheel. Make sure the string and cable are in the grooves as you put pressure back on them and you should be set to go.
If you use the "turn the limb bolts out" method the only thing that's really important is to count the turns and turn each one out the same amount. If the bolts are bottomed out you can get about 11-12 turns and the rigging should be slack. Watch the threads through the barrel nut.
As the guys said, it takes about 10 minutes if you know what you're doing. 15 minutes if you don't.
Mess it up and we'll be here for you.
If You're Not Living on the Edge You're Taking Up Too Much Space
Martin/Rytera Staff Shooter
PSAA Life member, UBP Life member
PADI AOW Diver