I just wrote these out in the order I found them, it's not the order you have to go in, but here is where all 21 pieces are:

1. Downstairs in the apartment building, outside Faina's house past the mailbox.
2. Inside Faina's house.
3. Ontop of the Vodka Bar roof.
4. Ontop of Arban's Salon rood.
5. The Cemetery Bench.
6. Bench to the left of Town Hall.
7. Ontop of Town Hall.
8. Doctor's Volkov's office.
9. Backroom of Oleg's general store.
10. Evgeny and Anastasia's bed.
11. Evgeny and Anastasia's garden.
12. Backroom of Roman's Bookstore.
13. Backroom of Vodka Bar.
14. Forest - As far to the left as you can travel.
15. Lover's Island past Hookah Lounge before Shore.
16. Ontop of The Countess' Manor.
17. Trofim's Shed - Against the far left wall.
18. Inside Hookah Lounge.
19. Demyan and Marusia's House.
20. Ontop of Nikolina's House.
21. Inside of Nikolina's House.