An adverb is a word that describes a verb. It is usually found following shortly after the verb or it may be found at the beginning of a sentence. Additionally certain kinds of adverbs describe adjectives. The adverb usually describes how, when, where, or to what degree an action took place.
Shortly after the verb:
The bugle corps played Taps slowly after the names of the dead were read.
At the beginning of the sentence:
Unfortunately, the man in the hat didn't respond to the signal I gave him regarding his zipper.
Note: The adverb at the beginning of a sentence should always be set off with a comma.
An adverb describing an adjective:
The incredibly ugly man found his attraction to bats was mutual.