but try to be as level as you can. The cement will maybe run a little under the mold where there may be a slight gap, but that's ok. Just try to keep the mold level too. But it will be much easier if you get the ground as level as you can first. And use a flat piece of 2x4 or something to level the mold off before smoothing it with the trowel. Youtube videos as well for reference. Good luck!