The decision tree is designed to help you choose which analysis is best for how you want to analyze your data. To use the decision tree, all you have to do is choose the best option that best answers the question or statement. Continue to answer the questions until an analysis is selected that meets the criteria you provided. As you answer questions, you will see the decision tree being highlighted, so you can see the decisions being made and see its path.
After the decision selects an analysis, you can click the Conduct Analysis link. If you have your project already selected, then the analysis modal will come up for you to provide the inputs and add the analysis to your document in the analysis tab. If there is no project selected, then a dialog will notify you saying that a project must be selected first.