it did note that the state officially calls them "poll challengers" though "watcher" is the common term and the one used most in the email. (And watching is really what you mostly do.)
I considered signing up but the choice of shifts was 6:30 AM to 1:00 PM and then from 1:00 to 8:00 - or when the last voter left which will certainly be later than 8. If I had decided to sign up, I would have had to go to a training (on line) and that I would be sent a letter from the party confirming I had completed the training, was the party's designated representative, and what precinct I had been assigned to. The letter, along with my I.D. would have to be presented to the chief election judge in the precinct as soon as I arrived.
It went on to say that watchers really aren't there to challenge voters but more to make sure no interference with voting. Any problems would be reported to the phone numbers (I assume to the DFL or Secertary of State) that the poll watchers/challengers would be given.
Each party is allowed to have 1 and only 1 representative in polling place at any time.