To create a new collection "class":

var Books = Backbone.Collection.extend({
    // books will be sorted by title
    comparator: "title",

    initialize: function(models, options) {
        options = options || {};

        // (Optional) you can play with the models here
        _.each(models, function(model) {
            // do things with each model
        }, this);

        this.customProperty = options.property;
    },
});

All the properties are optional and are there only as a demonstration. A Backbone.Collection can be used as-is.

Then using it is as simple as:

var myBookArray = [
    { id: 1, title: "Programming frontend application with backbone" },
    { id: 2, title: "Backbone for dummies" },
];


var myLibrary = new Books(myBookArray, {
    property: "my custom property"
});


myLibrary.each(function(book){
    console.log(book.get('title'));
});

Will output:

Programming frontend application with backbone
Backbone for dummies

We need to define a collection with a url property. This is the url to an API endpoint which should return a json formatted array.

var Books = Backbone.Collection.extend({
    url: "/api/book",
    comparator: "title",
});

Then, within a view, we'll fetch and render asynchronously:

var LibraryView = Backbone.View.extend({
    // simple underscore template, you could use 
    // whatever you like (mustache, handlebar, etc.)
    template: _.template("<p><%= title %></p>"),

    initialize: function(options) {
        this.collection.fetch({
            context: this,
            success: this.render,
            error: this.onError
        });
    },

    // Remember that "render" should be idempotent.
    render: function() {
        this.$el.empty();
        this.addAll();

        // Always return "this" inside render to chain calls.
        return this;
    },

    addAll: function() {
        this.collection.each(this.addOne, this);
    },

    addOne: function(model) {
        this.$el.append(this.template(model.toJSON()));
    },

    onError: function(collection, response, options) {
        // handle errors however you want
    },
});

Simplest way to use this view:

var myLibrary = new LibraryView({
    el: "body",
    collection: new Books(),
});

By default, the url property is not defined. Calling fetch() (while using the default Backbone.sync) will result in a GET request to the results of url.

var Users = Backbone.Collection.extend({

  url: '/api/users',
  
  // or
  
  url: function () {
    return '/api/users'
  }

});

var users = new Users();
users.fetch() // GET http://webroot/api/users