Yes this is the way to go, it took a hell of a long time and a bit of crying but now all my dlc's show as installed.
As an addition to this you have to drag and drop each file 1 by 1, you cannot create a folder containing them all and drag that folder into the android/data/ourlife.demo.apk folder as it will not show up as downloaded (at least it didn't for me), you need to drag them all into the android/data/ourlife.demo.apk/files folder, then create a game folder and place them all in there. The game folder is also very important as only dragging them into the file folder will not have them show up as installed.