Verb Placement
Verbs always go second in a sentence.
Even if the subject isn't first, the verb goes second.
Example:
I am eating an apple.
Ich esse einen Apfel
Example:
Tomorrow we go to school.
Morgen gehen wir zu schule.
Since tomorrow(morgen) was put in the first position, we(wir) had to be moved to third so the verb could still be in the second position.
So what if there are two verbs in a sentence? Then one verb gets kicked to the end.
There can't be two verbs in the second postion, so one of them must get moved to the end of the sentence.
Example:
I want to eat an apple.
Ich will einen Apfel essen.
Usually, the verb that comes first in the english sentence, is the one that stays in second position in the german sentence.
The verb that gets moved to the end must have the "-en" ending on it.
SOURCE: http://www.jabbalab.com/blog/880/how-german-verbs-work-in-the-present-tense-part-1