Update README

README.md

@@ -3,3 +3,81 @@
 This library allows you to define Gmail filters in PHP, and then generate XML that you can import into Gmail's filter settings
 
 Inspired by https://github.com/antifuchs/gmail-britta.
+
+## Installation and Basic Usage
+
+### Step 1: Require the Library
+
+```bash
+composer require opdavies/gmail-filter-builder
+```
+
+### Step 2: Create Your Filters File
+
+Create a `filters.php` file that returns an array of `Filter` objects.
+
+For example:
+
+```php
+<?php
+
+require __DIR__ . '/vendor/autoload.php';
+
+$filters = [];
+
+// Add your filters.
+
+return $filters;
+```
+
+### Step 3: Generate the XML
+
+Run `./vendor/bin/generate-filters > filters.xml` to generate the XML for the filters and export it into a file.
+
+### Step 4: Import the Filters
+
+Log in to your Gmail account and import your filters using the generated XML file.
+
+## Available Methods
+
+### Conditions
+
+_Conditions that a message must satisfy for the filter to be applied:_
+
+- `has` - can be used to check for various properties, such as attachments, stars or labels. Can also be used as an alternative to some of the following methods previously - e.g. `from:john@example.com` - and can be useful for more advanced queries.
+- `hasNot` - the opposite of the above.
+- `from` - if the message is from a certain name or email address.
+- `to` - if the message is to a certain name or email address.
+- `subject` - if the message has a certain subject.
+- `hasAttachment` - if the message has an attachment.
+- `excludeChats` - exclude chats from the results (false by default).
+
+### Actions
+
+_Actions you can apply to messages that match the conditions:_
+
+- `label` - add a label to the message.
+- `archive` - archive the message (skip the inbox).
+- `labelAndArchive` - both add a label and archive the message.
+- `spam` - mark the message as spam.
+- `neverSpam` - never mark the message as spam.
+- `trash` - delete the message.
+- `read` - mark the message as read.
+- `star` - star the message.
+- `forward` - forward the message to another email address.
+- `important` - mark the message as important.
+- `notImportant` - mark the message as not important.
+- `categorise` - apply a smart label to the message.
+
+## Filter Examples
+
+```php
+// If an email is from a certain address, add a label.
+Filter::create()
+    ->from('john@example.com')
+    ->label('Something');
+```
+
+## References
+
+- [Search operators you can use with Gmail](https://support.google.com/mail/answer/7190?hl=en)