Here video how it’s done. Not that hard just if you have general knowledge and skills? Except bending over door and laying down (you can take door off, but I didn’t) I marked burner tube where it separates to make sure I got seated down all way. I found easier to unplug wire connect from back access hole.
It you think you can do this yourself you will mostly have to install the connector on wires in new box they are made for several types installations. Don’t worry about which wire goes where, it’s loop system and just need to connect loop. Don’t worry about the crack in front of heat shield if you’re cracked, looks like most crack there. Like I said hardest part bending down and laying on floor. I unplugged the 110V cord and pulled unit out get access to Back cause I don’t like working with powered.
https://www.youtube.com/watch?v=T2lHx3IsdT0