[openwallet-foundation-labs#38]Add comments on README example

Signed-off-by: Lukas <Lukas@hopae.io>

README.md

@@ -52,18 +52,36 @@ Here's a basic example of how to use this library:
 ```jsx
 import sdjwt from '@hopae/sd-jwt';
 
+// Define the claims object with the user's information
 const claims = {
   firstname: 'John',
   lastname: 'Doe',
   ssn: '123-45-6789',
   id: '1234',
 };
+
+// Define the disclosure frame to specify which claims should be disclosed
+const disclosureFrame = {
+  _sd: ['firstname', 'lastname', 'ssn'],
+};
+
+// Issue a signed JWT credential with the specified claims and disclosure frame
+// return a Encoded SD JWT.
 const credential = await sdjwt.issue(claims, privateKey, disclosureFrame);
 
+// Define the presentation frame to specify which claims should be presented
 const presentationFrame = ['firstname', 'id'];
-const presentation = await sdjwt.present(encodedSdjwt, presentationFrame);
 
-const verified = sdjwt.verify(presentation, publicKey, ['firstname', 'id']);
+// Create a presentation using the issued credential and the presentation frame
+// return a Encoded SD JWT.
+const presentation = await sdjwt.present(credential, presentationFrame);
+
+// Define the required claims that need to be verified in the presentation
+const requiredClaims = ['firstname', 'id'];
+
+// Verify the presentation using the public key and the required claims
+// return a boolean result
+const verified = sdjwt.verify(presentation, publicKey, requiredClaims);
 ```
 
 Check out more details in our [documentation](https://github.com/openwallet-foundation-labs/sd-jwt-js/wiki)