Creating and designing a visualization typically involves a process that starts off with an original research question followed by finding, collecting, or gathering your data, cleaning and organizing your dataset so that it is in the correct format to be finally visualized. Often times this is an iterative process that may involve
question > find/collect/gather data > clean and organize data > visualize data
After collecting, organizing, and processing your data, you will have to figure out how to best visualize your data. Don't fret, there are many "chart choosers" out there that can help you out. The most important thing is finding what insights and observations you want to highlight in your dataset. Trying out several different kinds of visualization types (chart types) in an exploratory manner will be extremely beneficial and allow you to reflect and iterate on creating the best visualization possible to communicate your message.