No clue on RPGM, but that would be awesome to play Treasure of Nadia on mobile.
As for mods, there's two ways I go about it if you're loading a zip/rar but not an APK. Not sure about modding APK files. These steps assume you already downloaded the game, the mod, but haven't unzipped anything yet. It also assumes the mod file is supposed to go into the "game" folder that every RenPy game usually has. If it needs to go in another location within the game folder, you can do that as well. Once its on the device, the folder structure is identical to being on the desktop.
Installing Mod from Computer:
- Unzip the game into a folder.
- Navigate to the /game folder within the zip (assuming that's where the mod should go)
- Drop the mod in there
- Rezip the game into an archive
- Copy to phone or tablet
- Install like normal with Spark, it'll copy the contents including the mod during the install
Installing Mod from Phone/Tablet:
- Install the game using the import like normal for Spark
- Close the spark app in the background. Not sure if that matters but I do it to be safe.
- Go into the Files app on your iPhone or iPad
- Locate the mod file, and select "move" from the menu
- If it brings up a section other than "Browse", like iCloud for example, hit the back arrow in the upper left until you're in the main Browse section of files.
- Select "On my iPhone/iPad"
- Select "Spark" which should be a folder midway down with the Spark logo on the folder icon
- Select "Games"
- Select the folder that matches the name of the game you installed
- Select the "game" folder
- Select "Move" in the upper right corner.
- Do a test launch of the game in Spark. It should be installed now.