How do I program a room service system [on hold]

The idea of this program is too ask for the user's input on what the customer would like for room service. An example is it will ask if the customer likes food, meal or beverage. And in each option, it also has other options. After that, it can be done again if the customer likes another thing and will display the total amount of each option that has been chosen. I am currently doing this for a Programming Class project. I know how to code....but not so sure how to execute this idea. And a little extra, maybe you could tell me how to make a backing option? Like if the option chosen is wrong and the program is able to go back