This is a regular verb. It follows the conjugation pattern of the verb falar.
Present:
A Ana grita quando fica animada.
A Ana grita quando fica entusiasmada.
Ana shouts when she gets excited.
Preterite:
O Miguel gritou por ajuda.
Miguel shouted for help.
Conditional:
(Eu) gritaria mais alto.
I would shout louder.