You need to select the tracks which you want to export first. They then get rendered as .wav to a folder on the SD card. You can access either via usb or insert the SD into your computer. It's pretty straight forward.

I really really love the workflow of live mixing / bouncing the tracks on the Tascam and then only export the main tracks that I later want to eq for example. Do you get the idea? Not sure if I made it clear..