Add docs

Author: veewee

README.md

@@ -11,6 +11,19 @@ This package contains a cache wrapper for the SOAP engine.
 
 Want more information about the future of this project? Check out this list of the [next big projects](https://github.com/php-soap/.github/blob/main/PROJECTS.md) we'll be working on.
 
+# Prerequisites
+
+You can choose what cache implementation you want to use.
+This package expects some PSR implementations to be present in order to be installed:
+
+* PSR-7: `psr/cache-implementation` like `symfony/cache` or `cache/*`
+
+Example:
+
+```sh
+$ composer require symfony/cache
+```
+
 # Installation
 
 ```shell
@@ -23,8 +36,23 @@ This package provides engines that can be used in a generic way:
 
 ### CachedEngine
 
+You can cache a complete engine so that you don't have to reload a WSDL on every HTTP request.
 
 ```php
+use PhpSoap\CachedEngine\CachedEngine;
+use Soap\CachedEngine\CacheConfig;
+use Soap\Engine\Engine;
+
+$engine = new CachedEngine(
+    $yourPsr6OrPsr16CachePool,
+    new CacheConfig(
+        key: 'cached-engine',
+        ttlInSeconds: 3600 
+    ),
+    static function (): Engine {
+        return new YourSoapEngine();
+    }
+);
 ```
 
 ## Drivers
@@ -33,5 +61,21 @@ This package provides drivers that can be used in a generic way:
 
 ### CachedDriver
 
+You can cache a complete driver so that you don't have to reload a WSDL on every HTTP request.
+
 ```php
+use PhpSoap\CachedEngine\CachedDriver;
+use Soap\CachedEngine\CacheConfig;
+use Soap\Driver\Driver;
+
+$driver = new CachedDriver(
+    $yourPsr6OrPsr16CachePool,
+    new CacheConfig(
+        key: 'cached-engine',
+        ttlInSeconds: 3600 
+    ),
+    static function (): Driver {
+        return new YourSoapDriver();
+    }
+);
 ```