My girlfiriend just purchased a 2017 Acadia and can’t figure out how to get the seats in the 3rd row to lock into place. Not sure if there’* an issue with them or what the trick may be? Thanks in advance!

They should just pull back and lock. Make sure you're not pulling the strap for the "lock" part of that (release the strap and pull the seatback instead). If it doesn't work at this point, check to make sure the release straps actually move in and out against the spring when you pull them. If they don't, they might be broken or jammed up with dirt or junk of some sort.