To set the track number field for a downloaded recording from a link, first you'll need to associate the recording to a Release. Click here to learn how to do that.
Once the recording is associate to a Release, a corresponding track will exist on that Release. This is where you'll set the track number. Here's how:
1. Open the Release either by double-clicking it in the Releases tab OR by clicking directly on the Release in the recording edit modal.
2. Click "Edit" on the Release page to make the Release fields editable.
3. Double-click the track to open the track edit view.
4. Enter the track number in the Track sequence field and click Save to save your changes.