Script Plugin Development

We are currently building a script plugin to integrate with our inhouse application. Started following the example given here here: Part 1 How to deploy Adaptivist ScriptRunner scrip... - Atlassian Community

But we are getting stuck at the following situations from the example:

  1. Scripted Fields: We tried to implement the steps in the example but the scripted fields do not get created.
  2. Custom scripts are not available on the scripts folder to be execute using the console
  3. Can the script plugin have a admin UI? We plan to use the UI to update the credentials that will be used by the plugin to store data.