First, find the "nous" form of the present tense of the verb and remove the "ons".
Add the following endings dependant on the person: JE-AIS. NOUS-IONS TU-AIS. VOUS-IEZ IL/ELLE/ON-AIT. ILS/ELLES-AIENT
The only exception is "être". The stem of "être" is "êt-".
All but "être" follow this rule, however verbs which are irregular in the present have their iregularity passed on.
