add details about credentials configuration in README file

Author: DenisaCG

README.md

@@ -19,6 +19,36 @@ To install the extension, execute:
 pip install jupyter_drives
 ```
 
+## Configure Credentials
+
+To begin using the extension and gain access to your drives, you need to configure your user credentials generated by the provider (e.g.: `access_key`, `secret-access-key` and if applicable `session_token`).
+
+For those working with `S3` drives using the `AWS` CLI, the credentials will be automatically extracted from `~/.aws/credentials`. There is nothing that needs to be done on your side.
+
+>Note: This is only applicable for Linux or macOS `AWS` CLI users. In case you are using the `AWS` CLI from Windows, you can use the custom file path configuration with `C:\Users\USERNAME\.aws\credentials`. You can read more about this [here](https://docs.aws.amazon.com/cli/latest/userguide/cli-chap-configure.html).
+
+### Configuration file
+Otherwise, you can add your credentials to the server configuration file. Create a `jupyter_notebook_config.py` file in one of the
+[Jupyter config directories](https://jupyter.readthedocs.io/en/latest/use/jupyter-directories.html#id1),
+for example: `~/.jupyter/jupyter_notebook_config.py`, and specify your long-term or short-term credentials.
+
+```python
+c = get_config()
+
+c.DrivesConfig.access_key_id = "<AWS Access Key ID / IAM Access Key ID>"
+c.DrivesConfig.secret_access_key = "<AWS Secret Access Key / IAM Secret>"
+c.DrivesConfig.session_token = "<AWS Session Token / IAM Session Token>"
+```
+
+### Custom file path containig credentials
+You can also just specify the location of a local file which contains your credentials. The `acccess_key`, `secret_access_key` and if applicable the `session_token` will be automatically extracted from there.
+
+```python
+c = get_config()
+
+c.DrivesConfig.custom_credentials_path = "path/to/file/containing/credentials"
+```
+
 ## Uninstall
 
 To remove the extension, execute: