How to install a dryer vent:
2. Drill through the other side of the wall, then go outside to find out where your hole is.
3. Fail to find hole.
4. Drill a hole from the outside at the measured point you expect the inside hole to be. Go inside to check where you came out.
5. Fail to find hole.
6. After much headscratching, realize that the wall is two layers thick - remember how the carriage house was built in 1909 of brick? And how its walls are therefore about a foot thick? The structure of this wooden wall, which replaced a garage-door thing, is plywood - insulation - more plywood - more insulation - third layer of plywood.
7. Go to Menards and buy a keyhole saw to cut out the hole in the middle layer of plywood.
8. Discover that the studs on the two layers don't line up. Now what are the odds that the more-or-less random spot I chose for my dryer vent should be precisely centered on a stud on the other side? See the hole I drilled?
9. Cut another damn hole three inches to the right. Plan to buy a little cover panel for this one.
10. Success! I can finally drill a hole from the outside that I can see on the inside. So cut out the hole on the outside.
11. Don't forget to lay a bead of caulk under the vent hood on the outside before fastening it to the wall.
12. Bask in the glory of your finished dryer vent!