I received, along with my welcome guide and potassium iodide tablets

, a Schnuppper-Abo card that allows me to travel free on buses in the zones 100-101 around Bern. However I can't figure out how to use it or rather, how to start using it. I understand that it somehow needs to be used first to activate the 7 day limit and I was wondering how do you do that?
Is that what those little orange boxes are for?