There are total 8 shops of the map, you'll only need to burn down 6 of them

Click video walkthrough section for a video walkthrough,
or the shops sections bellow for a picture + brief description of the location

Direct timelines: (or click the video's description)
1. Fish Chips 00:05
2. Surf Store 00:19
3. Bar 00:32
4. Lobster Shop 01:08
5. Big Bar 01:30
6. Garrys Tools 02:18
7. Liquor Store 02:51
8. Sandy Store 03:21

South side of the map, on the steet near the marina

South side of the map, on the steet near the marina, right side of the Fish Chips

South side of the map, on the steet near the marina, right side of the Surf Shop

East side of the map, walk north from the bar and you'll see it, it has some boats parked near it

Southeast side of map, near the train tracks, there's a basketball court near it, walk east from the bar and you'll see it

East side of the map, walk north from the Lobster Shop and you'll see it, it has some boats parked near it as well

Northwest side of the map, walk north from the hotel and you'll find it

Mid side of the map, right side of the hotel

Be caution that the rent shops/ garages/ port office doesn't count as shops
Also some shops takes a while for the merchandise in it to collapse and count as burned

The guide's picture is from the offical Destructive Creation faceook
https://www.facebook.com/destructivecreationsteam

Happy hunting