Find the button/slider with the “braille bumps” on the side of the Flip:
Pull back the slider
Until the USB plug pops up:
If you are using a desktop PC or you don’t have easy access to the USB ports on your computer, attach the extension cable:
Slide it in so it’s fully connected:

The other end looks like this, and needs to go into one of the USB ports on your computer:

[...] Flip: Connecting to a PC [...]