Since nobody responded on how to make it work the only way I managed to is to dl the obb file listed under the apk. Won't work with the original azure lane playstore obb for some reason
1. Install azur lane (google play).
2. Log in, download all files.
3.Delete Azur Lane (just move the shortcut to the trash). Install Azur Lane Mod (do not enter the game).
4. Find Android/obb. Create folder "com.YoStarEN.AzurLane" if it is not there
5. Move the file obb to this folder. start the game, download all the files again. The mod works.