Create extra Uart on ItsyBitsy M4

Would like to create an extra Uart on the itsybitsy, am using Ardunio coding.
Have found
Trying to figure out which Sercom ports are available. Using original SPI, I2C and Uart. so don’t want to kill them.
have looked at the Schematic and the ports seem different to the ones stated in the linked document.
Was planning to use D10 and D11 on SERCOM1.

Have run out of Digital pins can I use A4 and A5 and what are their Digital equivalents?

You can find the answer in the Arduino documentation.

Placed a query on Adafruit forum and got a answer in case someone is interested