Here's a free advent calendar you can print and modify with your own photos instead of the disreputable cartoons I've supplied.
As well as that, why not add notes? Here, I'll start...
Here are the instructions. If they're not clear, I suggest farting around with it until it works:
1. You'll see one of the pictures (see the set with the rest of the pictures) is marked 'right'. This is the right-hand-side f the calendar. You'll need to cut the left edge of the sheet where the rooftop and the wall are. The 'fuzzy' bit near the bottom you can just cut out approximately.
2. Do the same sort of thing for the 'left' sheet, this time cutting along the right hand edge.
3. Overlap the right hand side and left hand side so that the RHS building seems to stand in front, like in the completed picture. Glue it down.
4. Now open up the windows and doors by cutting round three sides of the boxes printed. You can concoct other ways if you like.
5. Trim away the bottom right hand corner of the sheet called 'inside right' so that when 'inside left' sits underneath , the overlap doesn't cover up the nativity scene.
6. Stick 'inside left' to the back of 'left', lining up edges and windows with figures.
7. Do the same to 'Inside right'
8. Cut out the shed/manger.
9. stick it down