Verb conjugation of "ärgern" in German

I will add a feature to the dictionary builder tool, that marks a word as vulgar. The words that are shown in the tool are words that users did not find in our dictionary and a lot of them are vulgar.
Today the temperature rose above 30 degrees Celsius and we don't have an air condition at the office which means that working is almost impossible. Rick told all his employees to go home or to the beach and work in the evening.
In school, we now are learning the grammar part, more specifically, the participles and so on. I understand it at all, but the conjugations, boy they are tough. A lot of patience is needed.