Kittens need a lot of playtime with their litter-mates or cat owners. At that tender age, having a partner to play with is extremely helpful for their overall development and well-being.
If you only have a small kitten and no other cat in the house, what you can do is spend plenty of playtime with your kitten and provide stimulating interactive toys for your little one.
Kittens love playful fights. It is a way for them to bond with their litter mates. In order to recreate that you can play with your kittens, just like the person does in the video below: