Seeed Round Display with Seeeduino Xiao - SAMD21

Hello, i just ordered a seeed round display with an Seeeduino SAMD21.

What Pins on the SAMD21 are still usable when connected to the display? I wanna connect a rotary encoder to the Seeeduino and using the UART … Possible or are the pins already used for communication with the display?

btw : i only need the display, i dont want to use the touch function.

with best regards