How do you solve a classification machine learning problem using R?

Machine learning algorithms seem to be used carelessly on a trial and error basis without proper understanding about how they work. This guide will introduce you to the fundamentals of the classification machine learning problem using R and how you can apply this into data sets that will generate value for your business. What is a classification machine learning problem in a nutshell? Goal: To predict if an object belongs to one category or the other. Example: To predict if a user stays or leaves a firm.