diff --git a/docs/extensions/composer.md b/docs/extensions/composer.md
index 435907ec..c6474f85 100644
--- a/docs/extensions/composer.md
+++ b/docs/extensions/composer.md
@@ -1,4 +1,52 @@
 Using Composer Packages
 =======================
 
-[todo] Using Composer packages: This might be evident, but we should write a paragraph or two about it nonetheless.
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+By default, after installing Bolt you will get two composer files: `composer.json`
+and `composer.lock`. Those files are there to manage the dependencies of your
+project. Dependencies are third-party libraries that your code needs for it to
+execute correctly.
+
+For example, in the `composer.json` file in your project, you'll see something like this:
+
+```json
+"require": {
+  "php": ">=7.2.9 || ^8.0",
+  "bolt/core": "^5.0"
+  "bolt/assets": "^5.0",
+}
+```
+
+As the key of each dependency in `require` you'll find the name of the dependency,
+like `php` and, yes, `bolt/core`. The value specifies the version constraints, i.e.
+the versions of the third-party packages that your code is compatible with. `^5.0` means any version that is `5.0`
+or higher, but lower than `6.0`.
+
+### Managing dependencies
+
+You can install packages using `composer require`, for example:
+
+```
+composer require bolt/forms
+```
+
+To remove:
+
+```
+composer remove bolt/forms
+```
+
+To update a specific package
+```
+composer update bolt/forms
+```
+
+To update all packages
+```
+composer update
+```
+
+The above commands will update *both* `composer.json` and `composer.lock`. Simply put, `composer.json` keeps the 
+configuration and version constraints of your project. `composer.lock` keeps the exact versions of all packages
+that you got with the most recent update command.
+
+For more details, check [semantic versioning](https://semver.org/) and the [Packagist repository](https://packagist.org/).
diff --git a/docs/extensions/entities.md b/docs/extensions/entities.md
index 290c68e4..41924ba1 100644
--- a/docs/extensions/entities.md
+++ b/docs/extensions/entities.md
@@ -3,6 +3,113 @@ Doctrine Entities (managing content)
 
 Read more about this topic in Doctrine's official documentation: [Doctrine ORM][docs].
 
-[todo]
+## What are Entities?
 
-[docs]: https://www.doctrine-project.org/projects/orm.html
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+Entities are, simply put, PHP objects that allow CRUD (create-read-udpate-delete) operations
+with the database.
+
+Thinking of traditional SQL databases, you can think of an Entity as a row in a table in the database.
+
+The entity class serves two purposes:
+
+1. Define the columns and properties of the table in the database (i.e., what fields does it store)
+2. An a PHP object, store the data for a specific instance (row)
+
+For example, a very basic entity can be defined as a `Product`:
+
+```php
+<?php
+
+class Product
+{
+    /**
+     * @var int
+     */
+    private $id;
+    /**
+     * @var string
+     */
+    private $name;
+}
+```
+
+## What Entitires does Bolt provide?
+
+Bolt contains a number of entities:
+
+| Entity     | Description |
+|------------|-------------|
+| `Content` | Stores a single instance of a `record`. For example, it can be a `page`, `showcase` or a `block` |
+| `Field` | Stores a single instance of a field data, for example it's `type`, `name` and `content` it belongs to. |
+| `Relation` | Stores a relation between two `Content` entities.  |
+| `Taxonomy` | Stores a single instance of a taxonomy, like it's `name`, `slug`, `type` and `content`. |
+| `User` | Stores a single instance of a `user`, including their `name`, `displayName`, `email` and hashed `password`. |
+| `Log` | Stores a single instance of Bolt's built-in logger. |
+| `Media` | Stores a single instance of files that Bolt is aware of, such as files uploaded through [FileFields][filefields] and [ImageFields][imagefields] | 
+
+
+## How to create your own Entity?
+
+You can add Entities directly in the `src/Entity/` directory of your project.
+
+For example, let's create a new Field type `color`, which will be an entity.
+
+In `src/Entity/` create a class `ColorField.php`:
+
+```php
+<?php
+
+declare(strict_types=1);
+
+namespace Bolt\Color;
+
+use Bolt\Entity\Field;
+use Bolt\Entity\Field\Excerptable;
+use Bolt\Entity\Field\RawPersistable;
+use Bolt\Entity\FieldInterface;
+use Doctrine\ORM\Mapping as ORM;
+use OzdemirBurak\Iris\Color\Hex;
+
+/**
+ * @ORM\Entity
+ */
+class ColorField extends Field implements Excerptable, FieldInterface, RawPersistable
+{
+    public const TYPE = 'color';
+
+    public function getValue(): ?array
+    {
+        $value = parent::getValue();
+
+        if (empty($value)) {
+            return [];
+        }
+
+        $color = new Hex($value[0]);
+
+        return [$color];
+    }
+}
+```
+
+Then, make sure the entity is properly mapped by Doctrine, by addding to your `services.yaml`:
+
+```yaml
+### Map entities
+doctrine:
+  orm:
+    auto_generate_proxy_classes: '%kernel.debug%'
+    naming_strategy: doctrine.orm.naming_strategy.underscore
+    auto_mapping: true
+    mappings:
+      Color:
+        is_bundle: false
+        type: annotation
+        dir: '%kernel.project_dir%/src/Entity/ColorField'
+        prefix: 'App\Color'
+        alias: Color
+```
+
+[docs]: https://www.doctrine-project.org/projects/orm.html
+[filefields]: /fields/file
+[imagefields]: /fields/image
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