How to bind popups to Leaflet layers?

So, I’m trying to make a map using geoJSON. My layer has a lot of points, so I’m using circle markers for performance. I’m a bit unclear on how to chain the pointsToLayer method and an onEachFeature function.

Currently, my code looks like this:

L.geoJSON(features, {
  pointToLayer: function(feature, latlng){
     return L.circleMarker(latlng, circleMarkerOptions);
     }}).addTo(mymap);
});

The current code works, but I haven’t had much luck with the syntax of attaching the popups to the individual features.