Make playing in the playpen challenging by filling it with all kinds of stuff like houses, tubes, sand bath and other stuff. It is important to also use items that already have the smell of your hamster. This helps your hamster get used to the space and gives a familiar feeling.
Therefore, avoid large heights in the playpen and, for example, do not place houses against the edges of the playpen.
Very important! Don’t leave a hamster alone in his playpen, so you can always keep an eye on things.