It not understanding how to use these cards. EX. I have 3 Unstoppable Convictions and I attack i can use all three of choose enhances on the same attack?

Unless a restricion on the card itself says otherwise, yes, you may use multiple copies of the same enhance. as long as the enhance comes from a different source it is a new enhance that is being played. (exceptions are E's that state that they may be played multiple times)