Added instructions

Author: Kotsias, Panagiotis-Christos

README.md

@@ -6,11 +6,17 @@
 
 # etherscan-python
 
-Minimal python API for [etherscan.io](etherscan.io).
+A minimal python API for [etherscan.io](etherscan.io). 
+
+Most of the free webhooks from the [Accounts](https://etherscan.io/apis#accounts), [Contracts](https://etherscan.io/apis#contracts), [Transactions](https://etherscan.io/apis#transactions) and [Tokens](https://etherscan.io/apis#tokens) modules are supported.
+
+ Their example use-cases are summarized [here](https://api.etherscan.io/apis).
 
 ## Installation
 
-Assuming [conda](https://docs.conda.io/en/latest/miniconda.html) is already installed in your system, first create the environment:
+Before proceeding, you should register an account on etherscan.io and generate a personal API key to use. 
+
+Assuming [conda](https://docs.conda.io/en/latest/miniconda.html) is already installed on your system, first create the environment:
 
 ``` bash
 conda env create -f env.yml
@@ -30,11 +36,30 @@ pip install .
 
 ## Run unittests
 
- 
-
 ``` bash
- conda activate etherscan-python && bash run_tests.sh
- ````
+conda activate etherscan-python && bash run_tests.sh
+````
+
+## Usage
+
+In `python` , create a client with your personal etherscan.io API key:
+
+``` python
+from etherscan.client import Client
+
+api_key = YOUR_API_KEY
+config_path = "etherscan/configs/stable.json"
+
+client = Client.from_config(config_path, api_key)
+```
+
+Then you can call all available methods, e.g.:
+
+``` python
+client.get_eth_balance(address="0xddbd2b932c763ba5b1b7ae3b362eac3e8d40121a")
+
+> ('40891631566070000000000', 'OK')
+```
 
 ___
 Powered by [Etherscan.io APIs](https://etherscan.io/apis).