Help required for creating a action

I am planning to create a action which will basically login to NSX using REST API  and then create a array which will store the value for transportzone.

I created a workflow with REST api for testing and it worked.

Now i am trying to create the action using the same working code.

But i am not able to understand how i will connect using REST in this mode ,

I cannt get a option to select my NSX manager which i have added in orchestrator because there is not option to select the defined REST API.

What can i do in code in order to have  the REST API enabled

I am apasting the code that i am trying to use.I am new to programming and hence if there is any mistake in the code plz let me know.

/ Return a list of all the EDGE-IDs in XML format (string)

// Note: this works only with the first PAGE of the edge, 200 edges per page

// Prepare  request

var arrAuthenticationParams;

arrAuthenticationParams = ["Shared Session", "admin", "PXXXXX"];

var objRESTAuthentication;

objRESTAuthentication = RESTAuthenticationManager.createAuthentication("Basic", arrAuthenticationParams);

var host_url = 'https://NSX IP Address/api'

var nsxManagerRestHost = RESTHost(host_url); 

var request = nsxManagerRestHost.createRequest("GET","/2.0/vdn/scopes");

request.contentType = "application/xml";

// Esecute request

System.debug("Querying list of first 200 EDGEs");

//System.debug("Request URL: " + request.fullUrl);

var response = request.execute();

// Evaluate the response

//System.debug("Response Status Code: " + response.statusCode);

if (response.statusCode == 200) {

    //System.debug("EDGE list is " + response.contentAsString);

    System.debug("Response is Success!");

}

else {

    throw("Failed to get EDGE list! ");

}

// Return XML response   

//edgeList = response.contentAsString;

edgeList = response.contentAsString;

System.debug ("Reslut:" + edgeList);

return edgeList;