I've done it and it's more time consuming than anything. I didn't have a manual or Tony so I just figured out a way to do it.
Depending on the setup, Tony can advise you which way is easiest.
I have an older model and I can't get access to the burn pot easily because of the hood deflector. I think some models you can get access to the burn pot and pull it out from that end.
For mine, I just take the 6? bolts holding the bin assembly and pull the whole thing out. Disconnect the electrical of course. Take the two wires for the igniter out of the control box (takes a very small jewels screwdriver to undo the set screw).
Gain access to the burn pot, mine has screws on top. Take those out, pull out the burn pot and get access to the igniter. Undo the set screw, pull out the bad igniter.
KEY POINT. the most difficult part of this is running the new igniter cables through the burn pot/aug box out to the controller. I just tape the ends of the news ones to the old ones and pull them through. think about this before you do it. It's kinda like running wire through a wall. Do it right and it's perfect, do it wrong and how you gonna fix it?
Not real specific, but I don't know which model you have and Tony is great with it.
Next time I do it, I'll take photos along the way.
Russ