At least you should tell if you need to program certain hardware or you'll just simulate the function. Then, try to read a book explaining the interface between keypad and LCD which is very famous. Finally, if you have questions come and ask.
As a start you may read "8051 Microcontroller and Embedded Systems", by Muhammad Ali Mazidi because it explains all the concepts that you need to understand but in C language. However, being engineer it will be a peace of cake to write hdl code after that.
Sameh Yassin