You can transfer the games between the Steam and Android versions, but it does require some technical knowledge into the Android Operating System.
Anyway, you can find the files on your Android device at the following location:
/data/br.com.beholdstudios/knightsappsamsung/files/...
In that folder, there should be a file called
data.kopp
If you want to sync your progress, you'll have to manually swap it between the one in your Steam folder at:
.../SteamApps/common/Knights of Pen Paper/knightspp_Data/...
All you need to do is replace one file with each other to sync. It's that simple.
However, you'll need to root your Android device first and have a method of moving files around, such as
Root Explorer.