To extend the legs, slightly loosen one of the Leg Lock Grips. This should allow you to extend the leg to the desired height. Be sure to tighten the Leg Lock Grip once you have extended the leg to the desired height.
You should only have to loosen the Leg Lock Grip to the extent shown in the photo.
Do not loosen the Leg Lock Grip to the point where the grip falls off of the leg. This will upset the ability for the grip to lock the leg to the desired height.
To fix the legs at a desired angle, you will want to lock the Leg Adjustment Lock. Located towards the top hinge of the leg, the Leg Adjustment Lock can be unlocked and locked to position the Tripod around uncomfortable angles.
When you are finished using the tripod, make sure you lock the Leg Adjustment Lock once the tripod is back in its storage position, so that the legs cannot loosely swing around.
Once you are finished using the MeFoto Roadtrip Tripod, make sure that it is returned in the storage position, shown in the image on the right. Additionally, make sure that all grips are tightened, and adjustment locks locked, so that the legs do not move freely around.