When you create a new Space, there’s an autocomplete field called "Parent Space" where you can type and select the desired parent space. As soon as you select a parent, the new Space automatically becomes a Child Space of the one you chose.

This allows you to easily organize spaces into a parent-child hierarchy right at the time of creation.

Channels don’t have a parent-child relationship structure like Spaces do. Only Spaces can be assigned a parent space through the "Parent Space" autocomplete field during creation. Channels are independent by design and work like tags