RedBoard Turbo Hookup Guide
Alex the Giant 
Reinstalling Circuit Python
If you decided to do your developing in Arduino, you'll find that upon loading up your first sketch via Serial Upload, that the RedBoard Turbo no longer pops up like a removable USB device as it did previously. That's to be expected, so don't panic. In this section we'll walk through a few simple steps to getting Circuit Python re-uploaded onto your computer.
Reset board to Bootloader
We want the board to reset to the UF2 bootloader which as mentioned above, enables the board to act like a flash drive. To do that we'll take the steps mentioned underneath the troubleshooting section: we'll double tap the reset button. Shortly after you do that, the board will pop up as a USB drive named TURBOBOOT.
Drag and Drop Circuit Python Firmware
From here, it's a simple drag and drop to success. Download
the Circuit Python Firmware below (also found in the Github Repo under the
Firmware folder). Drag the contents named turbo-boot_cp.uf2 onto your
TURBOBOOT USB drive and the folder should disappear momentarily only to
reappear as a CIRCUITPY USB drive instead.