There’s no touch driver itself built in at the moment. You have to create the driver yourself and when you receive touch events from your driver, you pass the data (x, y, up/down, timestamp) into the UI library via RaiseTouch and RaiseButton.
For the UD700, it’s the ER-TFT070-4 display with the ER-TPC070-6 touch panel which has the FT5316 driver chip. It has a similar API to the Display NHVN, so you can adapt that driver.
Of course we plan to have touch drivers for these display soon. But this should get you going for now.