Adverbs are words that describe verbs...such as quickly, happily, ect.
An adverb tells HOW, WHERE, WHEN and TO WHAT EXTENT
Such as:
The child speaks cleary. Clearly is an adverb because it tells HOW a child talks.
They sing well. Well is and adverb because it tells HOW they sing.
He looked up. Up is and adverb because it tells WHERE.
The most important thing to remember is a word is not a part of speech until it is in a sentence. So look for the word that tells, how, where, when and to what extent in the sentence!
Hope that helps. I could go into more detail, but in 5th grade that should be enough!