Being at equilibrium does not mean the reaction has stopped. The forward and reverse reactions keep going at the same rate, so the numbers simply stop changing. Here you can see both at once: the particles still swapping while the counts hold steady, and the two rate bars coming out equal.
The conditions panel changes the temperature and the size of the vessel, and the add buttons put more of a substance in. The moment you change something the graph takes a step, and after a while it settles flat again at a new height. That is Le Chatelier’s principle.
Raising the temperature pushes towards the endothermic side; squeezing the vessel pushes towards the side with fewer gas molecules. But if both sides have the same number of molecules, squeezing does nothing. Compare the four in the reaction panel.