add sharer usage to readme

Author: Ian-Nara

README.md

@@ -2,18 +2,36 @@
 
 The UID 2 Project is subject to Tech Lab IPR’s Policy and is managed by the IAB Tech Lab Addressability Working Group and Privacy & Rearc Commit Group. Please review [the governance rules](https://github.com/IABTechLab/uid2-core/blob/master/Software%20Development%20and%20Release%20Procedures.md).
 
-This SDK simplifies integration with UID2 for those using Python.
+This document includes:
+* [Who Is this SDK for?](#who-is-this-sdk-for)
+* [Requirements](#requirements)
+* [Install](#install)
+* [Usage for DSPs](#usage-for-dsps)
+* [Usage for UID2 Sharers](#usage-for-uid2-sharers)
+* [Development](#development)
+  * [Example Usage](#example-usage)
 
-## Dependencies
+## Who Is this SDK for?
+
+This SDK simplifies integration with UID2 for DSPs and UID Sharers, as described in [UID2 Integration Guides](https://unifiedid.com/docs/category/integration-guides).
+
+## Requirements
 
 This SDK supports Python 3.6 and above.
 
-## Quick Start
+## Install
 
-Connect to the UID2 service, refresh the encryption keys, and then use the keys to decrypt an advertising token, to arrive at the corresponding advertising ID:
+The SDK can be installed using pip.
+```
+pip install uid2-client
+```
+
+## Usage for DSPs
 
+Connect to the UID2 service, refresh the encryption keys, and then use the keys to decrypt an advertising token, to arrive at the corresponding advertising ID:
+For examples of usage for DSPs, see [sample_client.py](examples/sample_client.py) and [sample_auto_refresh.py](examples/sample_auto_refresh.py)
 ```
-from uid2_client import Uid2Client, decrypt
+from uid2_client import Uid2ClientFactory
 
 # for UID2 (for EUID use EuidClientFactory)
 client = Uid2ClientFactory.create('https://prod.uidapi.com', 'my-auth-token', 'my-secret-key')
@@ -23,12 +41,33 @@ decrypted_token = client.decrypt(advertising_token)
 print(decrypted_token.uid2)
 ```
 
-Additional examples are in the [examples] directory:
-* [sample_auto_refresh.py](examples/sample_auto_refresh.py)
-* [sample_client.py](examples/sample_client.py)
-  * Example for DSPs (decryption of tokens)
-* [sample_sharing.py](examples/sample_sharing.py)
-  * Example for Sharers (decryption/encryption of tokens/uids)
+## Usage for Sharers
+
+A UID2 sharer is a participant that wants to share UID2s or EUIDs with another participant. Raw UID2s must be encrypted into UID2 tokens before sending them to another participant. 
+For examples of usage, see [sample_sharing.py](examples/sample_sharing.py) and [sample_auto_refresh.py](examples/sample_auto_refresh.py)
+
+```
+from uid2_client import Uid2ClientFactory
+
+# for UID2 (for EUID use EuidClientFactory)
+client = Uid2ClientFactory.create('https://prod.uidapi.com', 'my-auth-token', 'my-secret-key')
+client.refresh_keys()
+```
+Senders:
+
+1. Call the following:
+```
+encrypted = client.encrypt(raw_uid)
+ ```
+2. If encryption was successful, send the token `encrypted.uid2` to the receiver.
+
+Receivers:
+
+1. Call the following:
+```
+decrypted = client.decrypt(uid_token)
+```
+2. If decryption was successful, use the token `decrypted.uid2`.
 
 ## Development
 
@@ -56,7 +95,7 @@ Get access to an interactive shell within the Python 3.6 Docker image:
 make shell
 ```
 
-## Example Usage
+### Example Usage
 
 To run all the example applications: