You could do it all on your site with the Google API, but I wouldn't recommend it. I'd just add a link to google maps for directions. Try this:
Step 1: Go to Google Maps. https://www.google.com/maps
Step 2: Switch to “directions” mode.
Step 3: Enter destination only. Leave starting point empty. ...
Step 4: Go to menu.
Step 5: Choose option “Share or embed map”
Step 6: Copy URL and use it as a directions link. And that's it.