ok using the serial number you provided the test proceedure is basically the same except you use the lift function on the ground control, raise the unit to full height and take a pressure reading and then set the pressure according to the data on the dataplate on the lift. The dataplate/sticker should have the hydraulic pressure listed on it.
if you cannot get it to achieve the correct pressure then you may have a faulty relief valve or a worn out pump or a bad steer cylinder packing.
checking the steer cylinders is fairly straight forward, get a bucket to catch the fluid, steer it to one side, then remove the line from the one side of the closed end of the cylinder and activate the steer direction and check for any bypass fluid, there shouldn't be much coming past the packing. if you get alot of flow with any pressure behind it then its bypassing, bad packing. You can try to repack the cylinder but check the cost of just replacing it, it might be more cost effective to just order a new cylinder. (replace both cylinders, if one is worn out the chances are the other one is too).