diff --git a/README.md b/README.md
index 61e84b3..508a193 100644
--- a/README.md
+++ b/README.md
@@ -6,9 +6,33 @@ Inspired by the [gmail-britta](https://github.com/antifuchs/gmail-britta) Ruby l
 
 ## Usage
 
-TODO
+* Run `composer require opdavies/gmail-filter-builder` to download the library.
+* Create a new PHP file and require `autoload.php`.
+* Create an array of `GmailFilter` objects, each with it’s required methods.
+* Pass the filters into an instance of `GmailFilterBuilder`.
+
+```php
+require __DIR__ . '/vendor/autoload.php';
+
+$filters = [];
+
+// Add filters.
+$filters[] = GmailFilter::create();
+
+...
+
+// Display the output.
+print GmailFilterBuilder($filters);
+```
+
+To generate the output, run PHP on the file - e.g. `php generate.php`.
+
+By default, the output is displayed on screen. To generate a file, use the greater than symbol followed by a file name - e.g. `php generate.php > filters.xml`.
+
+## Example
+
+For a working example, see the [opdavies/gmail-filters](https://github.com/opdavies/gmail-filters/blob/master/generate.php) repository.
 
 ## License
 
 MIT
-