You can use Strava to create routes, I don't use Strava so cannot advise.

I have used RideWithGPS and prefer that as it is also my cycling fitness tracker. Its pretty easy to create a course, as Garmin calls it, or a route, as RWGPS calls it, using the on-line website. It's free, though I'm paying for a subscription as I like the service it provides. Once you create a route, you save it.

The easiest method to get that saved route to the 1000 is to install a Garmin iQ app on the 1000 called RideWithGPS, it's in the iQ store. Note that you need to have the Garmin Connect Mobile app installed on a smartphone, you then download from the GCM iQ store. GCM will install that app to the 1000. Once that iQ app is on the 1000 you access the iQ apps, RWGPS and select to view and download the routes, then go to navigate on the 1000 and start.