Update OEKG-SPARQL WEB API docs

Author: jh-RLI

docs/oeplatform-code/web-api/oekg-api/index.md

@@ -15,19 +15,28 @@ In this document we describe how you can access the contents of the OEKG via Web
 
 Here is an example of how to query the Open Energy Knowledge Graph (OEKG) using SPARQL using python and the requests library for http requests.
 
+!!! Info "OEP-API Token"
+
+    For authentication with the OEP-REST-API you have to register on <https://openenergyplatform.org/accounts/signup/> or sign in with you institution.
+    Once you are registered you can find your API Token in you Profile page under the "Settings" Tab. Clicks "Show Token" and copy the hash value.
+
+    See our more detailed guide on [how to get started with the OpenEnergyPlatform](https://openenergyplatform.github.io/academy/courses/02_start/#how-do-i-get-started-with-the-oep).
+
 ```python
 import requests
 
+OEP_API_TOKEN = "<Add-Your-Token>"
+HEADER = {"Authorization": f"Token {OEP_API_TOKEN}"}
 sparql_endpoint = "https://openenergy-platform.org/api/v0/oekg/sparql/"
 payload = {
     "query": """SELECT ?s ?p ?o
                 WHERE {
                   ?s ?p ?o
-                }"""
+                }""",
     "format": "json"
 }
 
-r = requests.post(url=sparql_endpoint, json=payload)
+r = requests.post(url=sparql_endpoint, json=payload, headers=HEADER)
 print(r.json())
 ```