Marita, I had problems with finding one piece & it's probably this one so......SPOILER BELOW.......
Face the corner where the blue door meets the wall. Door on the right side of the corner. There's a light fixture hanging from the ceiling. Look up. The scrap is the same color as the background, so just look for the outline of it.
I think you light the incense in the gamescreen, not inside inventory. Not sure why yours wont light.
The incense must be on the "altar" for it to light.
Hope this helps & allows you to play instead of work.