On the left of the map, there is a platform with the hole where the mice spawn. The cheese is located at another platform on the right of the map. Between the two platforms there are some small cloud supports.
To solve this map, some mice should turn into large planks and cover the gaps between the cloud ground so that the normal mice can walk over them.
It is possible to beat this level by yourself. This is done by being a long plank, landing on the cloud, unplanking, jumping a bit forward, planking again to land on the cloud, and repeating. It takes a bit of getting used to, though. Also, trolls will sometimes turn into a large box, an anvil, or otherwise interrupt your movements so watch out for them.