Update README

README.md

@@ -1,2 +1,55 @@
-### Install using composer
-```composer require codeonweekends/mpesa-php-sdk```
+# Install using Composer
+```composer require codeonweekends/mpesa-php-sdk```
+
+# Usage
+The easiest way to use the API is by calling ``Codeonweekends\Mpesa\Mpesa`` and accessing
+the available transaction methods.
+
+- Create an instance of ``Codeonweekends\Mpesa\Mpesa``
+- Get the api context using the ``getApiContext()`` method
+- Set the public key and the api key on the context using ``setPublicKey(YOUR_PUBLIC_KEY)`` and ``setApiKey(YOUR_API_KEY)`` respectively
+
+Example:
+```php
+$mpesa = new Codeonweekends\Mpesa\Mpesa();
+$context = $mpesa->getApiContext();
+
+$context->setPublicKey(YOUR_PUBLIC_KEY);
+$context->setApiKey(YOUR_API_KEY);
+```
+
+
+## Create a C2B Transaction
+
+```php
+$thirdPartyReference = 11114;
+$amount = 10;
+$customerMSISDN = 258843330333;
+$serviceProviderCode = 171717;
+$transactionReference = 'T12344C';
+
+$c2b = $mpesa->c2b($thirdPartyReference, $amount, $customerMSISDN, $serviceProviderCode, $transactionReference);
+```
+
+## View a Transaction Status
+
+```php
+$queryReference = '5C1400CVRO';
+$serviceProviderCode = '171717';
+$securityCredential = 'Mpesa2019';
+$initiatorIdentifier = 'Mpesa2018';
+
+$status = $mpesa->transactionStatus($queryReference, $serviceProviderCode, $securityCredential, $initiatorIdentifier);
+```
+
+## Transaction Reversal
+
+```php
+$amount = 10;
+$serviceProviderCode = 171717; 
+$transactionID = '49XCDF6';
+$securityCredential = 'Mpesa2019';
+$initiatorIdentifier = 'Mpesa2018';
+
+$reversal = $mpesa->transactionReversal($amount, $serviceProviderCode, $transactionID, $securityCredential, $initiatorIdentifier);
+```