Playlists within a playlist

[k_kaiser85]

I notice some channels have more categories in their playlists other than the "Created Playlists"

A channel by Bio Rad Laboratories does this.
how do they get playlists within a playlist?

 

[Hirudov]

In the channel layout editor you select multiple playlists for new section, then you name this new section and you can add playlists to it. It's playlist containing playlists. Very useful feature if your channel has different topics to cover and you want your viewers not lost in the videos, but watching only what interests them.

 

[k_kaiser85]

Life. Saver. Thanks !