There are hex screws keeping the igniter in place. I think they were 5/16...so you have to have a socket wrench. The space is kind of tight, and it's all on the right side, so if you're left handed (like I am) it's going to be a challenge to get the hex screws out without dropping them. Dropping them isn't too bad if they don't fall into the hole the gas pipe is coming through. Unfortunately one of them fell in there, and there's no getting it out of there. I had a machine screw that fit, so I used that when I put the new igniter back in.
The gas pipe is held in place with a mounting machine screw in the back of the oven. You should remove that first to allow a little movement in the gas pipe to have a little room to move your hands around. The bottom hex screw on the igniter is especially cramped.
Tools you'll need are Phillips screwdriver, socket wrench with 5/16 socket.
To sum up:
1. Have one or two spare hex screws on hand if you happen to have them...or just don't drop them.
2. Remove the racks from the oven.
3. Remove the bottom plate by removing the two screws at the back holding it in place.
4. Remove the gas pipe guard plate by removing the two screws at the back and push and pull and wiggle it out of place and pull it out.
5. Remove the machine screw in the back holding the gas pipe in place.
6. Remove the hex screws.
7. Unplug the igniter.
8. Plug in the new igniter.
9. Replace the two hex screws.
10. Replace the machine screw in the back holding the gas pipe in place.
11. Replace the gas pipe guard plate.
12. Replace the oven bottom plate.
13. Replace the oven racks.
Boom.
All in all it took about 20 minutes, and it only took that long because I had trouble maneuvering the socket wrench with my right hand and dropped one of the hex screws down the pipe opening.