The one on the right (when you are facing the box) should wrap around the rear of the engine, and connect into the multi-port fitting. The one on the left, goes under the battery tray, and connects into the intake hose behind the passenger side headlight.
One question. Are you the original owner of the vehicle? If not, who knows what a previous owner of the vehicle could have done to the hose. If you are the original owner, the mechanic may have disconnected it while servicing the vehicle, and not been able to locate it's origin.
Differential fluid changes are easy, but difficult at the same time. Unless you don't mind spending a few hours on the ground or getting gear oil allover you, I would take it to a shop to get it done.
The easiest way I've found is to get a pan, place it under the differential, remove the bolts, remove the plate, let the oil drain out, clear any debris, replace the gasket, pour the required amount of oil into a thin plastic bag, cram the bag inside the diff housing, bolt it back up, torque it, take it for a spin, Good as New.
(DISCLAIMER: for the above paragraph. This takes time & patience, and a lot of wrestling with grimey stuck on parts. I do not recommend anyone do this unless they are prepared for the repercussions that may result from. I do not take any responsibility for any damage that may result from this advice.)