Identify all of the adverbs in the following sentence : how did you know about the game cancellation?

All the identified adverbs: "how", and "about". It's pretty easy to figure out the adverbs, all you need to do is use a dictionary or google the meaning of each word. When you do that, you get to see their parts of speech. In other words, whatever dictionary you're on, you can see if the word is an adjective, noun, verb, or an adverb. Then, you could choose which words are adverbs in the sentence.  Hope I helped. :)