A user put together the guide I've attached for using flic buttons with MobileSheets. Let me know if that helps get you the information you are looking for. I have a couple flic buttons myself for testing and they work fine if configured as an HID so that they send key presses like "page down".
That's a lot of work. The new Flic buttons has Universal Actions. If i e.g. program Push as arrow-right, and Double push as arrow-left, you can connect the button to any BT device. in MSP just use the button to perform pedal actions like next-page and previous-page. You don't need the App for this anymore.