The etrex series has primitive turn by turn capabilities. By primitive I mean effectively none. The way to navigate is with a breadcrumb gpx which shows up as a line on the display. Your location is a dot. Navigation is done by keeping the dot on the line.

The screen is such low resolution and contrast, that if you have both background map and your route turned on, you can't discern route from map.

When navigating on bicycle, turn the map off. Use your breadcrumb and dot to navigate. I probably rode 50k miles using an etrex exactly like that. If you miss a turn, you won't know until you notice your dot hanging out on and empty screen. Fun times.

If navigating on foot, maybe you can see well enough to use both map and breadcrumb.