If you create Defect from Tools - > New Defects - there are several action called.
I think you can start with Defects_DialogBox
You create a new DialogBox and it's filled in with defect fields, etc.
Use DebugView and see for yourself
[2784] WorkflowExecute: DialogBox(True, "New Bug")
[2784] WorkflowExecute: DialogBox Globals : TDConnection, User, Lists, Debugger, LibraryFolder_Fields, Bug_Fields, Actions, WorkflowHelper
[2784] WorkflowExecute: DialogBox(True, "New Bug") = UNASSIGNED
[2784] WorkflowExecute: Defects_DialogBox(True, "New Bug")
[2784] WorkflowExecute: Defects_DialogBox Globals : TDConnection, User, Lists, Debugger, LibraryFolder_Fields, Bug_Fields, Actions, WorkflowHelper
[2784] WorkflowExecute: Defects_DialogBox(True, "New Bug") = UNASSIGNED
[2784] WorkflowExecute: GetNewBugPageName(1, "Details")
[2784] WorkflowExecute: GetNewBugPageName Globals : TDConnection, User, Lists, Debugger, LibraryFolder_Fields, Bug_Fields, Actions, WorkflowHelper
[2784] WorkflowExecute: GetNewBugPageName(1, "Details") = UNASSIGNED
[2784] WorkflowExecute: Defects_GetNewBugPageName(1, "Details")
[2784] WorkflowExecute: Defects_GetNewBugPageName Globals : TDConnection, User, Lists, Debugger, LibraryFolder_Fields, Bug_Fields, Actions, WorkflowHelper
[2784] WorkflowExecute: Defects_GetNewBugPageName(1, "Details") = UNASSIGNED
[2784] WorkflowExecute: GetDetailsPageName(1, "Details")
[2784] WorkflowExecute: GetDetailsPageName Globals : TDConnection, User, Lists, Debugger, LibraryFolder_Fields, Bug_Fields, Actions, WorkflowHelper
[2784] WorkflowExecute: GetDetailsPageName(1, "Details") = UNASSIGNED
[2784] WorkflowExecute: Defects_GetDetailsPageName(1, "Details")
[2784] WorkflowExecute: Defects_GetDetailsPageName Globals : TDConnection, User, Lists, Debugger, LibraryFolder_Fields, Bug_Fields, Actions, WorkflowHelper
[2784] WorkflowExecute: Defects_GetDetailsPageName(1, "Details") = UNASSIGNED