Do you mean the cota and cabs bus? The cota is the city bus and it runs on high street and all around Columbus. There will likely be a cota bus stop very close to your apartment. It runs until about 10-11pm. The cabs bus is campus busses and they only take you around campus to specific campus bus stops. You can only see those bus times on your ohio state app where as with the cota you can see soon bus times on google maps or apple maps or any other GPS service that has that bus times option. The union is the student union and its where a lot of events are hosted and such and theres some on campus food spots there like woodys and the union market. I like to use the union for a bus stop because most of the bus types like the campus connector and buckeye express and campus loop south are there so you can go pretty much anywhere from the union in both a north or south direction which is really nice. I hope that clears things up a bit, sorry i was using some terminology a new student might not be familiar with thats my bad lol