If you're familiar with the support program (available at http://www.dynonavionics.com/docs/support_software.html), it's similar to a software upgrade, except you choose "retrieve logged data" instead of the usual "upgrade to version x.xx".
If you're not familiar with the support program, start from the above website, download the support program, then open it and click the help button. It has documentation contained within.
One more thing - if you've never connected to your D100/D120, and you have the Dynon USB-serial converter (if your laptop doesn't have a 9 pin serial port), you'll want to install the appropriate USB-Serial converter drivers for your operating system from that same page.