Welcome to politics. Rule #1 all politicians lie. Seriously you really think the president has any true powers to change anything? He needs Congress backing to change anything.
Actually, the president has lots of power. Granted, he does need congressional support in many cases. But if we have a partisan administration, the president and congress do not need to follow any laws or the Constitution. Consider Obama Care and Obama Motors as two examples.
He (or she) has the power of the veto. Consider the line item Veto. Hard to pass because congress likes being able to slip provisions to raise congressional salary into a "Stop Killing Kittens" bill that we all woulds likely support.
The president can simply veto all bills containing stuff not related to the actual bill. And the public will yell about a do nothing president unless the president explains why a particular bill was sent his way. Reading of all bi;ll;s by the president might convince people to start paying attention.
He has the power to hire Zars/Czars. Those people do not answer to Congress, only to the president.
He has the power to fire people.
He is the leader of the free world and commander in chief of the armed forces.
He can issue rules, and regulations called Executive Orders which have the binding force of law but do not require congressional approval.
The president has many powers.