When you ready with the firmware upgrade, you can disconnect the LP-16 from your PC.
In the uTool, first go to the settings and selet the LP-16 as target device.
Connect your USB storage device to your PC (HDD/SSD/USB thumb drive)
Select the Export tab in the uTool, then select the MultiTrack song subtab.
Click on the Add new song button, then browse the folder where your mono wav files located. (You need to make sure, the files are mono, and 44.1/48kHz 16/24bit) any other song will not displayed in the list.
When your mono files displayed in the Left window, you can start to create your song by drag and drop the mono files from the Left to the Right window.
When you successfully crated and saved a MultiTrack song select the song in the Left window and click on the export button at the bottom.
The song(s) copied to the USB storage device. When is done, you can disconnect the drive from the PC then plug it in the LP-16.