An adverb is a word that describes a verb, an adjective, and another adverb.
E.g :
He sings beautifully.
In this sentence, the adverb Beautifully describes the verb Sings.
The room is strangely quiet.
In this sentence, the adverb Strangely describes the adjective Quiet.
Ram is almost busy.
In this sentence, the adverb Almost describes the adverb Always