You need to modify the SiteMenu.ascx
control located in the ~/Sitefinity/UserControls/Navigation/
folder. Actually, we suggest you make a copy of the control and after that apply your changes because in case of upgrade you will lose the changes. As for the concrete implementation, please investigate the following online example:Click To Open
Also, could you explain what exactly you mean under "When i click on subpage1 or 2 i actually want it to pop up...
". If you want to open the pages in a new window, set "_blank" for the Target property of the menu item for the corresponding page in the method handling RadMenu OnItemDataBound event:
e.Item.Target = "_blank";
For more information on this matter have a look at this forum thread
Hope this helps.
the Telerik team