Concepts
Test (the simulator)
Try a flow in a pretend copy of your server before it goes live.
A pretend server
Test opens a copy of your server that only you can see. Click the panel's buttons, run the command or send a message there, and the flow runs as the bot would. Nothing reaches Discord.
Watch it run
The canvas lights up the path each run took, step by step, and a step that failed says why. Runs keeps the same record for the live flow.