bluetooth thermal printer

I need an Android Studio app,

I'm trying to send print commands to a bluetooth thermal printer, but no luck so far

It's a weird chinese printer and I need to connect to it from its official app, then I want to send print commands from my app

I have some classes from their SDK but no luck trying to use them,

I've attached the printer SDK and my poor attempt at developing the app,

I only need a button that triggers the printing of a 'Hello world' string

let me know if you can help me please,

thanks in advance

Pat

PS printer info
address = '66:22:F9:3E:F0:B9'
uuid = '00001101-0000-1000-8000-00805f9b34fb'
name = 'MHT-P58D'