Of course, there are countless other contexts and subtleties. May I suggest you get a grammar book, or at least study some very basic grammar on the net first. The conjugation of the verb "to be" is usually the first thing a person learns in any new language, and spoon-feeding basic grammar is not really a function of this site.
If you have any specific question about these verbs, we'd be happy to answer.
Student or Learner