A conjugation is the change of the verb according to the subject. For this endings (suffixes) are appended to the stem of the verb. First question is What is the stem? Well, it's the root without the endings.

German verbs in basic form always have the ending -en. That means that you take away the -en and you have the stem of the verb. Then you take the right suffix to append it to the verb and you have a perfect conjugation:

Even though it might have sounded difficult you'll find it easy since there are a lot of regularities.