Telehandlers are designed to handle rough terrain, but that doesn't mean they can be driven without regard for the terrain. Risk of tipping or load loss is great when traveling on slopes. If you must drive on a slope, keep the load low and proceed slowly, with great care. Before you get on the slope, downshift to a lower gear and four-wheel drive so you get engine braking to help control the telehandler's speed.
Avoid turning on a slope, but if you must turn, make the turn as wide as possible and use extreme caution. Never drive across steep slopes.
Ascend and descend slopes with the heavy end of the telehandler pointing up the incline. When there's no load on the forks, the counterweighted rear of the machine is the heavy end, so you should back up slopes. When the telehandler is loaded, the front of the machine is the heavy end, so you should back down slopes.