With a simple conjugated verb, most short, common adverbs go directly after it, unlike English, where they often go before: je mange souvent ici (I often eat here), not je souvent mange ici. Longer adverbs, especially those describing time or place (aujourd'hui, demain, ici, là-bas), have more flexibility and can also go at the very start or end of the sentence.
In a compound tense like the passé composé, short adverbs typically slot in between the auxiliary and the past participle: j'ai bien dormi (I slept well), elle a déjà fini (she has already finished) — a position that has no direct English equivalent, since English adverbs don't split a compound verb that way.