If you are trying to plan a route and want to use Google maps, here is a simple video showing you how to create one and export it to your GPS system.

http://www.youtube.com/watch?v=xW0zc3SILKA

http://hardkjarni.blogspot.com/2015/08/converting-google-maps-directions-to.html

http://labs.coruscantconsulting.co.uk/garmin/gpxgmap/convert.php