Restaurant Order System (ROS)

Question

Hi guys, I want to make such app which will do some thing like this

1) When a customer sits on a table a waiter gives him a tablet and the customer will order his food through Tablet in which this app is running.

2) Now when the customer ordered his food the order will go to the counter PC, after receiving an order on counter the counter user will generate a print of that order and set a timer to that customer that he/she will receive his/her food in just that minutes.

3) Now, at last when 1 minute were left the PC will generate a  alert to the counter PC that 1 minutes were left and when the order will placed to the customer the customer tablet will receive a message that your order is on table

Note: Please let me know that how can i design it and how many things should i use in it to develop this app, please use a easy language so that i will understand, as i am a beginner in Android, Thanks