Thanks for reaching out on the Community. We hope you don't mind us helping you in English, since this is the official Community language 🙂
Spotify doesn't play the next playlist in the list, even if they are in the same folder. The best way to make sure that one playlist plays after the other is to add the entire playlist to your Queue.
So, if there are two playlists that you would like to play consecutively, you play the first one, and then add the entire second one to the Queue by opening the playlist, clicking the three-dot menu and clicking Add to Queue.
Hope that answers your question! If you need any further help, let us know 🙂