The verb "seem" is similar to "be." It describes the impression made on the observer. Someone experiences something and then forms an idea. "Seem" is also similar to verbs such as "look," "feel," and "appear."
He seems thirsty.
He seems to be thirsty.
Is he hungry? I'm not sure, but that is my impression. That's my idea.
Those clouds seem to be moving our way.
He seemed like an honest person, but then we found out he wasn't.
They seem to be very happy.
(Notice that the infinitive "to be" often comes after "seem.")
This old computer doesn't seem to be working properly.
(The verb "seem" is often used with a negative.)
These shoes don't seem to fit. They're a little too small.
My guitar seems out of tune.
Life in the United States will probably seem a little strange to you at first, but you'll get used to it.
(The verb "seem" is in the simple form following the modal verb "will.")
Using U.S. currency might seem confusing at first, but after awhile you'll learn what things are worth.