A simple sentence is a sentence has only one independent clause with a subject, a predicate (which states what the subject is doing) and a complete thought.
Here, "The excited guest" is the subject, "ascended the stairs" is the predicate as it states the action of the subject, and "to the awards ceremony" is a complete though.
Thus, it is a simple sentence as it does not have any other dependent or subordinate clauses.
An example of a simple sentence can be "The mail man went home in a hurry".
