To plot to the plotter, see the Poster at Purcellville. There are also some helpful files here regarding changing the paper.
NOTE: Changing the paper is finicky, it can take several tries. Just try to roll it tight on the roll and then roll the paper slowly into the printer. You will here a beep and it will grab the paper. It will then take a bit to check it to see if it is straight, if not, it will kick it out and you try again.
Once the paper loads, it will confirm the paper type. If you have put in a different type, make sure to select that paper from the list. It makes a big difference in performance and smearing of your print.
Driver can be downloaded at:
https://support.hp.com/us-en/drivers/selfservice/hp-designjet-t610-printer-series/3339415
Here is the main HP Site for Information
https://support.hp.com/us-en/product/hp-designjet-t610-printer-series/3339415/how-to
I have also droppped a few of the more important files here.