The flowchart is a decision-tree posing answers leading to yes or no responses. It provides guidance as to whether you need to provide a reference in your writing.
The first question is 'Are you using someone else's ideas, theory, work or words?'. If the answer is NO there is no need to reference. If the answer is YES the next question to consider is 'is it a direct quote?'.
If the answer is NO several questions are posed all leading to the answer of YES, you do need to reference according to the required Style Guide. These questions are 'is it an indirect quote (paraphrasing)?', 'is it a summary of the main argument presented in a text (summarizing)?', 'is it a primary source?' and 'is it an author/information that someone else has referenced (secondary source)?'.
If the answer is YES to the question 'is it a direct quote' two questions are posed which lead to the answer YES, you do need to reference according to the required Style Guide. These questions are 'is it a primary source?' and 'is it an author/information that someone else has references (secondary source)?'.
In summary, you need to reference according to the required Style Guide if you are using someone else's ideas, theory, work or words.