diff --git a/main.js b/main.js
index cb61c244..b7be89b8 100644
--- a/main.js
+++ b/main.js
@@ -1,4 +1,13 @@
+/* global L Papa */
+
+/*
+ * Script to display two tables from Google Sheets as point and geometry layers using Leaflet
+ * The Sheets are then imported using PapaParse and overwrite the initially laded layers
+ */
+
 // PASTE YOUR URLs HERE
+// these URLs come from Google Sheets 'shareable link' form
+// the first is the geometry layer and the second the points
 let geomURL =
   "https://docs.google.com/spreadsheets/d/e/2PACX-1vS4sQJDfJGptqDkY-eNDqcR1xJ_YH-X0qb9BKnYvSf34ArSCPE5ducm_-FaG1cNcO1AgQjsjGxie8Fi/pub?gid=0&single=true&output=csv";
 let pointsURL =
@@ -10,13 +19,19 @@ let map;
 let sidebar;
 let panelID = "my-info-panel";
 
+/*
+ * init() is called when the page has loaded
+ */
 function init() {
+  // Create a new Leaflet map centered on the continental US
   map = L.map("map").setView([51.5, -0.1], 14);
+
+  // This is the Carto Positron basemap
   L.tileLayer(
     "https://cartodb-basemaps-{s}.global.ssl.fastly.net/light_all/{z}/{x}/{y}{r}.png",
     {
       attribution:
-        "© <a href='http://www.openstreetmap.org/copyright'>OpenStreetMap</a> © <a href='http://cartodb.com/attributions'>CartoDB</a>",
+        "&copy; <a href='http://www.openstreetmap.org/copyright'>OpenStreetMap</a> &copy; <a href='http://cartodb.com/attributions'>CartoDB</a>",
       subdomains: "abcd",
       maxZoom: 19,
     }
@@ -38,42 +53,40 @@ function init() {
   };
   sidebar.addPanel(panelContent);
 
-  let namesList = [];
-
   map.on("click", function () {
     sidebar.close(panelID);
   });
 
+  // Use PapaParse to load data from Google Sheets
+  // And call the respective functions to add those to the map.
   Papa.parse(geomURL, {
     download: true,
     header: true,
-    complete: function (result) {
-      addGeoms(result, namesList);
-    },
+    complete: addGeoms,
   });
-    Papa.parse(pointsURL, {
+  Papa.parse(pointsURL, {
     download: true,
     header: true,
     complete: addPoints,
   });
-
-  let options = {
-    valueNames: ["name"],
-    listClass: "names-list",
-    searchClass: "names-search",
-  };
-
-  let names = new List("sidebar-names", options);
-  names.add(namesList);
 }
 
-function addGeoms(data, namesList) {
+/*
+ * Expects a JSON representation of the table with properties columns
+ * and a 'geometry' column that can be parsed by parseGeom()
+ */
+function addGeoms(data) {
   data = data.data;
+  // Need to convert the PapaParse JSON into a GeoJSON
+  // Start with an empty GeoJSON of type FeatureCollection
+  // All the rows will be inserted into a single GeoJSON
   let fc = {
     type: "FeatureCollection",
     features: [],
   };
+
   for (let row in data) {
+    // The Sheets data has a column 'include' that specifies if that row should be mapped
     if (data[row].include == "y") {
       let features = parseGeom(JSON.parse(data[row].geometry));
       features.forEach((el) => {
@@ -82,11 +95,11 @@ function addGeoms(data, namesList) {
           description: data[row].description,
         };
         fc.features.push(el);
-        namesList.push(data[row].name);
       });
     }
   }
 
+  // The geometries are styled slightly differently on mouse hovers
   let geomStyle = { color: "#2ca25f", fillColor: "#99d8c9", weight: 2 };
   let geomHoverStyle = { color: "green", fillColor: "#2ca25f", weight: 3 };
 
@@ -100,7 +113,13 @@ function addGeoms(data, namesList) {
           e.target.setStyle(geomHoverStyle);
         },
         click: function (e) {
-          L.DomEvent.stopPropagation(e, click);
+          // This zooms the map to the clicked geometry
+          // Uncomment to enable
+          // map.fitBounds(e.target.getBounds());
+
+          // if this isn't added, then map.click is also fired!
+          L.DomEvent.stopPropagation(e);
+
           document.getElementById("sidebar-title").innerHTML =
             e.target.feature.properties.name;
           document.getElementById("sidebar-content").innerHTML =
@@ -113,10 +132,23 @@ function addGeoms(data, namesList) {
   }).addTo(map);
 }
 
+/*
+ * addPoints is a bit simpler, as no GeoJSON is needed for the points
+ */
 function addPoints(data) {
   data = data.data;
   let pointGroupLayer = L.layerGroup().addTo(map);
+
+  // Choose marker type. Options are:
+  // (these are case-sensitive, defaults to marker!)
+  // marker: standard point with an icon
+  // circleMarker: a circle with a radius set in pixels
+  // circle: a circle with a radius set in meters
   let markerType = "marker";
+
+  // Marker radius
+  // Wil be in pixels for circleMarker, metres for circle
+  // Ignore for point
   let markerRadius = 100;
 
   for (let row = 0; row < data.length; row++) {
@@ -134,13 +166,14 @@ function addPoints(data) {
     }
     marker.addTo(pointGroupLayer);
 
+    // UNCOMMENT THIS LINE TO USE POPUPS
+    //marker.bindPopup('<h2>' + data[row].name + '</h2>There's a ' + data[row].description + ' here');
+
+    // COMMENT THE NEXT GROUP OF LINES TO DISABLE SIDEBAR FOR THE MARKERS
     marker.feature = {
       properties: {
         name: data[row].name,
         description: data[row].description,
-        program: data[row].program,
-        client: data[row].client,
-        dropbox: data[row].dropbox,
       },
     };
     marker.on({
@@ -150,16 +183,12 @@ function addPoints(data) {
           e.target.feature.properties.name;
         document.getElementById("sidebar-content").innerHTML =
           e.target.feature.properties.description;
-        document.getElementById("sidebar-content").innerHTML =
-          e.target.feature.properties.program;
-        document.getElementById("sidebar-content").innerHTML =
-          e.target.feature.properties.client;
-        document.getElementById("sidebar-content").innerHTML =
-          e.target.feature.properties.dropbox;
         sidebar.open(panelID);
       },
     });
+    // COMMENT UNTIL HERE TO DISABLE SIDEBAR FOR THE MARKERS
 
+    // AwesomeMarkers is used to create fancier icons
     let icon = L.AwesomeMarkers.icon({
       icon: "info-circle",
       iconColor: "white",
@@ -173,14 +202,29 @@ function addPoints(data) {
   }
 }
 
+/*
+ * Accepts any GeoJSON-ish object and returns an Array of
+ * GeoJSON Features. Attempts to guess the geometry type
+ * when a bare coordinates Array is supplied.
+ */
 function parseGeom(gj) {
+  // FeatureCollection
   if (gj.type == "FeatureCollection") {
     return gj.features;
-  } else if (gj.type == "Feature") {
+  }
+
+  // Feature
+  else if (gj.type == "Feature") {
     return [gj];
-   } else if ("type" in gj) {
+  }
+
+  // Geometry
+  else if ("type" in gj) {
     return [{ type: "Feature", geometry: gj }];
-  } else {
+  }
+
+  // Coordinates
+  else {
     let type;
     if (typeof gj[0] == "number") {
       type = "Point";