A Test Suite is a collection of Test Flows that belong to specific tasks or feature, or have some other reason to be run together. When executed, if one of the flows fails, the Test Suite run will fail.
Let's take a look at the Test Suite page.
The Test Suite's navigation panel includes 7 tabs: Flows, Login, Parameters, Before/After, CI, Schedule and Collaborators.
The first and the most important tab where you write your flows.