Downloading Spotify playlists requires a Premium subscription. Here's how you can do it:

1. Open the Spotify app on your device.
2. Go to the playlist you want to download.
3. Toggle the "Download" switch to ON. It will turn green.
4. Wait for the songs to download. You'll see a green arrow next to each downloaded song.

Remember, you'll need to be connected to Wi-Fi to download the songs unless you have set Spotify to allow downloads over cellular. Also, downloaded songs are only available for offline listening if you remain a Spotify Premium subscriber.

Please note that downloading music from Spotify without a Premium subscription or using any third-party tools to rip music from Spotify violates Spotify's terms of service and is not recommended.