Camera offset and collison (Please help...)

Hello everybody, I've recently came across a third person tutorial and every thing went smooth.
My problem is that i want to expand it further. I am a bigginer with C# and i tried to add other pre-writen scripts on top of the existing script but it always got very buggy and glitchy... Below is the script i have for my camera and my player... please help

Thanks in advance, Guy.