New module in Web Designer


 I have reviewed the Web Designer documentation and searched the user forum without success. I created a new module in my project, and added a tab to the menu. How now to create sub-tabs in the menu item and where in my project (I mean the path to the IDM web server, so as not to install my web server) I can place a page where the user will go when clicking on the tab?
Thank you for your reply,