Hi,
if you’ve got a garmin bike device, i.e. a Garmin Edge, you don’t need Osmand 
for routing, you simply use your Garmin device.
For (online) route planning I prefer to use bikerouter.de. It’s simple, works great in a web browser, even on a smartphone and can export GPX files that you can open with Garmin Connect - and using on your Garmin device.
More information about the features you will find in Wanderlust - poi (supermarkt) neben gpx Track anzeigen - Webseite, App, Programm? - #3 by Vinzenz_Mai