Ok... first you're gonna need to correct drill bit for the OD of the tap... the tap itself, the helicoil, and the helicoil instalation tool.
1. Drill hole as perpendicular to surface as possible, do your best not to ream it out any.
2. Use the tap and tap the thread into the new hole, remember (for anyone who hasn't tapped before, use some sort of lubricant on the tap and don't forget to back track the tap every couple of turns to break off the cut material)
3. Clean out the hole
4. slide the part of the helicoil that cuts across the axis into the tool and start threading the coil into the tapped hole. (Cross axis peice should be first end into the hole)
5. ONce it's threaded in a couple threads deep in the hole, use a punch/needlenose/end of the insertion tool to break off the cross axis peice.
6. The fit of the coil into the thread should be pretty tight, thread a bolt of the correct size into the helicoil and tap it sharply with a hammer, this will help the coil to seat into the thread so it won't move.
I think that should about do it... if I"m not already too late or someone has more to add post it up