why do i need to make sure all my screens are blank and remove all my widgets? do i need to remove app shortcut icons too?
You want to clear your stock launcher's screens of widgets and shortcuts if you are going to keep the Launcher Pro (Plus = paid version -- well worth it). You do NOT want unused widgets operating in the background, draining your battery and also possibly creating conflicts with the LPP.
You can also download the free app Home Switcher from the Market where you can go back and forth at will between stock and dl launchers. Also, you can set or change the default launcher using this app.
I also recommend that, after installation of the new launcher, you do a battery pull (battery out, wait 60 seconds, put battery back, turn on). Gives the X a chance to settle in.