Trump knows very well how to achieve his goals. The problem with Trump is his lack of any discernible ethics, morality, or compassion. Not his lack of ability to gain power and accomplish his goals.
Everything about him and his actions and words reek of stupidity. He does not hold any understanding of the complexities of anything. He does not write. When he does, he misspells and uses incorrect grammar. He does not read. He has rudimentary understanding of basics. Etc.
So why is it that you find him to be intelligent? What exactly does he say or write that would lead you to this conclusion?
He has a genius for communication and persuasion that is undeniably effective. He understands the weak points in our political system and attacks them directly.
He's dumb when it comes to things educated people care about. But he's smart when it comes to getting what he wants.