Hello tristanr32276360,
Look at the documentation examples for api calls:
Web service calls
//from above documentation
var session = new SoapService(cnx, 'urn:xtk:session');
session.addMethod("Logon", "xtk:session#Logon",
["sessiontoken", "string", "Login", "string", "Password", "string", "Parameters", "NLElement"],
["sessionToken", "string", "sessionInfo", "NLElement", "securityToken", "string"]);
var res = session.Logon("", "admin", "pwd", <param/>);
var sessionToken = res[0];
var securityToken = res[2];
Hope this helps,
Marcel