It will still be a wavy line that you need to stick too, but there will be prompts that come up and in the top left there is a box which I assume you see, but it is empty? In this box it will tell you the upcoming prompt and count down the miles to that point. You get an arrow (straight ahead, bending left, bending right) and an abbreviated street name usually. It will also usually say which exit on roundabouts (occasionally gets it wrong but you soon know and can go back and correct yourself). Example you will see something like. 2nd Ext Strt with 3.0 mi below, where strt is the abbreviated street name, i.e. 3.0 miles until you should take the second exit onto street name. As you approach the point where you need to take action it pops up near the bottom of the current screen.
Very easy to use, just create route in ridewithgps, then go to you routes page under profile, click the one you want, then click .tcx to download it to you pc. Plug in the Garmin, mount it like a normal USB device like a pen drive, or access via my computer (don't go via the Garmin software etc go direct), then drag the .tcx into the folder called "new files". Unplug Garmin and turn it on, it will load up a bit slower, sometimes a few minutes (it is converting the files), just wait, once it loads check your courses menu, it will be there.