Sentence problems

How many subjects and verbs can I have in a sentence and how to recognize them in a sentence. Is there a rule that I should follow while forming a sentence like words order/sentence pattern (ex; subj, object, verb, then object subject verb) ex2; Before going to school you should eat your breakfast.
What confuses me is when I am forming a sentence and I have a word like "proof/prove" I do not know if I should put the verb/noun.