[README.md] better info about parameters

README.md

@@ -64,8 +64,16 @@ Crawlera middleware won't be able to handle them.
     make better usage of concurrency options and avoid delays.
 
 * `CRAWLERA_FETCH_DEFAULT_ARGS` (type `dict`, default `{}`)
-    Default values to be sent to the Crawlera Fetch API. For instance, set to `{"device": "mobile"}`
-    to render all requests with a mobile profile.
+    Default values to be sent to the Crawlera Fetch API. You can find parameters [on this page](https://docs.zyte.com/smart-proxy-manager/fetch-api.html#request-endpoint-parameters).
+    For example:
+
+```python
+'CRAWLERA_FETCH_DEFAULT_ARGS': {
+    'region': 'gb',
+    'waitfor_selector': '#cookieLoad',
+    'device': 'mobile'
+}
+```
 
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