Citaq H10-2 just eat EPOS tablet and thermal printer

[MCSstrike]

First this is a link to a previous discussion about this I found on this forum

I was wondering if anyone is able to help me with understanding how to write an android application for this Citaq H10-2 I got for free. From the thread I linked I have left a comment describing how to restore this tablet to a fresh version of android and about the test app I had found to demonstrate the EPOS's tablet and printer functions.

 

Next I would like to be able to write my own app which is able to display buttons on the screen and send things to print although I am unsure if it is possible to decompile the test apk I found and reuse some of the programming from that to enable my own app to print. I have some basic programming knowledge but I haven't written an android app before so any help would be greatly appreciated.