Some devices are limited as to the number of points in a single route. Older Garmin's limit was 40.
You say upload "directions", do you mean the route? To do that with the route on the screen, click 'data' in the menu bar and select 'export as .gpx' and then select where you want the file to go, which folder. Using GPS software like
Mapsource or Base Camp from Garmin you can open the .gpx file you just saved and drag it onto the device icon to load it into the device.