1. First, we need to find the music we like in Douyin. You can browse recommended music, search for specific music, or get music from other users' videos.

2. After finding the music you like, click on the music name or cover to enter the music details page. On this page, we can see the name of the music, the author and a "Set as Ringtone" button. Click this button to set this music as your cell phone ringtone.

3. If you want to edit music or add other effects, you can use some third-party tools or applications. For example, you can use audio editing software to edit and process music, or use a ringtone maker app to create personalized ringtones. These tools and applications usually have rich features and options that can help us create satisfying ringtones.

4. After setting the ringtone, we can adjust the ringtone volume, ring mode and other parameters through the phone's settings. The specific method varies depending on the mobile phone brand and operating system, but generally you can find options such as "Sounds and Vibrations" or "Ringtones and Notifications" in the "Settings" application of the mobile phone to set them.