you really aren't giving us much to go on.
try explaining to us all how far you have got.
i'm sure there are plenty of people here who can help you with specific questions but i don't think you will have much luck asking someone else to design your robot for you.
if you are looking for "howto" type tutorials, try searching the internet.
this link is a good example of the sort of thing you are looking for: http://robotroom.com/Sandwich.html
good luck with the project!