First you should set xGrid and yGrid under "File->Options". This defines, in which steps you can graphically input widgets.
Within the designer you always use the popup menu on the right mouse button. Now you can insert the widgets you want to use. Some parameters of the widgets can be input in the “Properties” dialog.
When you are ready with the design of your mask save it to disk and switch back to the editor.
Now you can use “Action->StartServer” and then “Action->pvbrowser” to start your initial pvserver.