TOPIC: "It seems or It seems that" and "He seems to&

Could you explain to me how to correctly use "It seems or It seems that" and "He seems to"?

You asked about the use of "seems", as in "It seems" or "It seems that" or "He seems to "Seem" is a linking verb like be, look,smell,feel, appear, and is thus followed by an adjective or noun complement."seem" or "seem to be" often is used to express some uncertainty about a subject, as in:
"You seem tired."
"The printer seems to be broken."
"It seems/It seemed" can be used as preparatory subjects for that-clauses and as if-clauses, as in:
"It seems that the meeting will last forever."
"It seemed as if the boss would never approve my going, but finally he did."
"There seems/There seemed" can also be used as preparatory subject for "to be",as in"
"There seemed to be no way out of the predicament."
Another important construction is "seem like", as in"
"Shanghai seems like an exciting city."