The Garmin Explore™ app can be used to set certain collections to sync to specific devices in the app.
For more information on Collections, see - Garmin Explore Website Collections.
Collections can be created directly in the Garmin Explore app.
Open the Garmin Explore app on your mobile device.
Select 
Saved.
Select 
New Collection.
Enter a collection name.
Select 
Add Items.
Select the items to add to the collection, then select Done.
Select Done to save the new collection.
Open the Garmin Explore app on your mobile device.
Select 
Devices.
Select the desired device.
Select Sync Settings.
Touch Sync Selection.
If prompted to select a primary collection, select the desired primary collection, then select 
(Android) or Save (iOS) when finished. Data in the primary collection is automatically set to sync to the device.
NOTE: Collections containing over 100 waypoints, 20 routes, 5 tracks, or a track with over 10,000 points may be too large to sync with your device and are marked with a yellow warning icon.
Touch the desired collections to toggle them to sync.
NOTE: Collections set to 
are set to sync to the device. Collections set to 
are not set to sync to the device.
Touch the back arrow when done.
The selected collections are now set to sync to the device. You will now need to sync your device.
For steps on how to sync the Garmin Explore app, see - Syncing the Garmin Explore App.