Like how to tell the difference Btween the 2

An adverb usually ends in "ly" and modifies any other part of speech. You can identify an adverb phrase because usually they will answer the questions where, why, when, how, and to what extent. Like in the phrase "he ran quickly", quickly would be the adverb because it modifies 'ran' and answers the question 'how'
A preposition introduces a prepositional phrase. For example "on the computer" or "in the yard" are prepositional phrases, so "on" and "in" would be the prepositions.

**To the twat below me: yes, as you said, an adverb USUALLY ends in 'ly' and answers all those questions, which is exactly what I said. Tell me how I was wrong exactly. I didn't say it ALWAYS ends in -ly.

an adverb is like quickly or fiercly. It is always a verb and usually ends in "ly". A prepostition is decribing where an object is in relation to another object such as "above the box"

Hope that helps!

The girl before me is wrong! An adverb answers the questions: When?Where?How?How often?To what extent? Yes it usually does end in -ly! But it doesn't sometimes as well! The word VERY is an adverb! Anyways, an Adverb is a word that describes a verb, adjective, or other adverbs!

A preposition is a word that relates to other words in a sentence and some common ones are for,before,became,of,etc....! Hope that is helpful!