Does the following sentence have any adverbs? If so, where?: A glow just barely appears on the northern horizon.
Yes, it has.
This sentence has two adverbs
just and barely.
This is called "word order" , in English you can't use any word by your way without proper grammar.
if you like to use adverb with a sentence, there are many rules over there. Among them one is after subject put the adverb if there is no auxiliary.