1. Device
Chrome / Edge · Connect, then Menu → ETC → SD (WAIT→OK). Opening USB may reboot Teensy — re-open SD after Connect.
2. Files
Drop files, folders, or .zip
- On device: Menu → ETC → SD, then connect here
↑↓ select · ← parent · → open folder · Enter play/open · Space play · F2 rename · drop files/folders/.zip to upload