First off, I am surprised that this kit only comes with 1 hide, as it is generally considered best to have 2, one in cool end, one over the UTH. You plug the thermostat into the UTH and it will regulate it.
Yes it was probably stress related, giving them a week to settle in is ideal. I know it's suuuuuper hard to be hands off for that long (at least it was for me) but it really is better overall for the snake's well being, both physical and mental.