Verb conjugation of "credere" in Italian

I hope my explanation was also clear that would say that for english verbs a to needs to be put from the selection list. Like: inhale would be 'to inhale' == 'inhalar'. The 'to' is taken from a selection list.
Drinking coffee at night is supposed to be bad. Why? I have no idea. I believe the contrary is true. Coffee opens my veins and let's blood flow better and quicker. I therefore have nicer dreams, mainly from my last vacation in Italy.
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.