Adverbs can act very similar to the adjective, in desriptive qualities and limiting factors. This can make adverbs tricky to locate in a sentence, or to use properly in writing. Adverbs modify verbs, hence the name. They "add" something to an existing verb. However, they can also modify adjectives and other adverbs. One key to locating adverbs is that they often end in -ly. What else can adverbs do? Adverbs can also . . .
a. introduce sentences.
b. connect independent clauses.
c. modify sentences and/or parts of sentences
If you're confused, look at the Venn Diagram below to see how adverbs and adjectives compare and contrast.
See examples of adverb usage below from my playthrough of the phenomenal video game, Alien: Isolation. MAKE SURE TO TURN ON "CLOSED CAPTIONS" TO VIEW ADVERB EXAMPLES.
Note: Look to the RIGHT of each clip to be aware of the game's ESRB Rating.