Update readme

Author: surajp

scripts/jsButton/README.md

@@ -1,4 +1,6 @@
-## These scripts assume you've a named credential named 'salesforce' created for your instance. The detailed steps for doing so are below:
+### Note:
 
-* Create an Auth Provider of type 'Salesforce'. You can either create your own Connected App or use the following consumer key and secret. The scopes should include `api` and `refresh_token` 
-* Create a named credential using the Auth Provider above and name it `salesforce`. The authentication type should be `OAuth`. For better security, I suggest you used `Per User` authentication so only authorized users can use the Salesforce APIs through the button
+Before using `sfapi`, take the following steps
+
+- Add your lightning domain (ends with `lightning.force.com`) to the `CORS` list under `Setup`.
+- Add your classic domain to `CSP Trusted Sites` list under `Setup`.