Start by locating your USB flash drive on your computer under This PC. Right-click on your USB flash drive and select Turn on BitLocker.
Tick the box Use a password to unlock the drive, enter your password in both fields, and click Next.
You must now choose to save your password so you do not forget it. We recommend that you either choose Save in a file or Print recovery key. Remember, however, that you should not store your printout together with your USB flash drive.