Goto The 'File' Menu at the top-left inside Dream Maker, choose 'New' and make a file of the Interface type. Play around with the window entitled 'default'. You can place and modify different types of preset window objects to able to achieve what you want for a template. If you plan on the window being resize-able, make sure you go into the settings for each object after choosing their size and position, going to the tab entitled 'anchors', and clicking the 'auto-set anchors' button.

Good luck!