RFID reading with arduino uno

Hi! I'm making an RFID scanner with an arduino uno

I'm using this IC: http://be.farnell.com/nxp/htrc11001t-02ee-11/reader-chip-contactless-hitag/dp/1902850

When I look at the datasheet, there are no fixed values for the next pins:
RX
TX2
TX1
XTAL1
XTAL2

So, I don't know how to calculate the clock, and everything on the left of the scheme, does anyone understand how to do this?

If you have any code that can help me out with programming this, or any wiring guides, tutorials etc. I would love to take a look at them!

Thanks!