While the process varies between hitch racks, it is always fairly simple. Most hitch bike racks have slots for the wheels, which you have to lift your bike up to in order to place them in. This helps stabilize your bike via the wheels, and then there are two arms that rotate and clamp down on your front and rear wheels – again, this is the design of many hitch bike racks, but not all.
Other hitch bike racks hold the bike via the top tube – so all you have to do is lift your bike onto the rack, and then secure it with the given straps. Make sure to consult the owner’s manual for your hitch bike rack, as the process of mounting your bike on the hitch rack can vary between devices.
Always double-check the rack and straps to make sure they are secure before driving off. This can usually be done in a matter of seconds, with a quick pull on each strap, just to make sure there is nothing loose.