To add samples to your library on the mobile app, click on the overflow menu (three vertical dots to the right of the sample).
Then select "Add to Library." All the sounds you download on the mobile app will sync to your Splice account and can be downloaded via the Splice desktop app once you're back at your computer. You cannot add presets, MIDI, or any pack extras from the mobile app currently.
Next, in order to download the sound to your device, please click "Download."
From there, you will be given the option to "Save to Files," which will save the sound on your phone, or to "Share" the sample.
If you choose to "Share" the sample, you can airdrop it to your computer, text it to a friend, etc.
Save to Files on iOS
To access your downloaded samples on iOS/iPad, make sure you're navigating to the Files app, and then going to "On My Device" > Splice > Samples. The Files app will oftentimes open to your iCloud Drive folder by default, which won't contain your Splice folder, so you'll need to go back a page, and then go into the "On My Device" folder, which is where the Splice folder automatically gets created.
Save to Files on Android
Samples you save to your mobile device will be saved to your Downloads folder, which is typically located at Files > Internal Storage > Download > Splice, but may vary by device.