laps function in 510?

[zill]

How does this function work?

Mine always shows 0.

[Quency]

I have an Edge 500 but it also has a lap function. I imagine the functionality is the same
you need to either press the "lap" button at the finish/start of each lap, or set up Auto-lap. auto lap is based on a preset distance.
I use strava - it will add a "Laps" tab to your activity and break up the distance/time/elevation/etc data into each lap for you which is handy for analysis.

[3DKiwi]

Have you tried pressing the button on the left?

You can also set up automatic lapping. Covered in the documentation.