Get input, calculate, print output (basic calculator)

I'm new to Bootstrap and wanted to make a simple calculator using the input boxes to get numbers, then the user would push a button and get an output.

I understand that you can add in javascript files but I'm having trouble just thinking of how to organize everything and how to run it. Any advice/examples would be really helpful.

Thanks!

In case you don't want to do all the coding yourself, http://www.jqueryscript.net/other/Customizable-Calculator-App-With-jQuery-Bootstrap.html

Saj