1) Make sure you pay attention to the Settings for the team relay division and get the one about bib number correct.  Also on the setup screen, there's a setting about "Allow same bib on consecutive splits". Leave this off if you'd never have the same person doing two consecutive legs. 
2) If you're importing relay teams from a spreadsheet, when you get to the 3 step import screen, use the Help button and see the suggestions for importing relay teams.
3) Be really, really careful about the exchange.  You should have the handoff after the person approaching has crossed the mat.  You should have the mat attended 100% of the time with someone that will be good at keeping those waiting far enough away that you don't get unwanted reads.