Sure, I can help with that. Here are the steps to make your Spotify playlist private:

1. Open the Spotify app on your device.
2. Go to "Your Library" located at the bottom right corner.
3. Select "Playlists" from the list.
4. Choose the playlist you want to make private.
5. Tap on the three dots (also known as the "ellipsis") located at the top right corner of the screen.
6. Scroll down and select "Make Secret."

Now, your playlist is private. Only you can access and listen to it.