Use a trailer jack by attaching the square metal component to the tongue of the trailer, ensuring the wheel or flat metal base is firmly on the ground. Wind the crank to extend the internal shaft and raise the trailer off the ground so that you may couple it with the hitch on a truck or leave it stationary for storage.
A trailer jack differs from a traditional car jack in that it raises through a telescoping mechanism rather than a jointed component, meaning it cannot carry as much weight but is able to fit securely on the trailer to eliminate the possibility of it slipping out. The jack has a square metal frame that fits around the tongue on the trailer, which is the metal piece that extends out from the front and connects onto a truck or other vehicle. To use the jack, place the frame around the tongue, and secure any fasteners or devices present.
Make sure the crank faces upwards and the wheel or base faces the bottom. Turn the crank to extend the telescoping section, and raise the front of the trailer off the ground. Do not raise the jack too high, as this may damage the system or the trailer. Let the crank rest comfortably at its nadir, and back the truck towards the trailer so you may couple the two together.