Bathtub Dimensions How Are Shower Panels Installed? Do I Need A Plumber? What About The Existing Diverter? What About A Tub Spout

How are shower panels installed? Do I need a plumber? What about the existing diverter? What about a tub spout - bathtub dimensions

PLUMBERS Please answer these if possible.

ps Showerpanel example is here:
http://www.masterfaucet.com/dimensions/i ...

and here:
http://www.masterfaucet.com/pictures/ima ...

At the moment I want to install a bathtub / shower facility and a shower panel in a way that still allows me to fill my bathtub with water as well as on. As the plumbing in this case? "I need 2 wind deflectors? Do I need a shower panel with built-in tub spout and what kind of flow in the nozzle do I need to effectively carry a standard 5 feet x 2 feet (or so) tub?

PS I saw so diy.com HGTV and direct reactions must be taken if you please!