In English when learning where the stress goes on a word there is no hard and fast rule. Take the word “refuse”, for example. It sounds different when you are talking about rubbish from when you don’t want to do something. The good news is no such problems exist in Spanish.

If a Spanish word does not have an accent the stress falls on the very last syllable unless it ends with a vowel or an “n” or an “s.” in which case the the stress will fall on the penultimate syllable again unless there is an accent telling you to put the stress somewhere else. That is broadly it. The one further detail is diphthongs where two vowels next to each other amalgamate into one vowel sound.  A classic example is the Spanish word “farmacia.” It sounds like you are talking about the mafia because there is no accent on the “i.” If the “i” had an accent, it would sound more like you would expect it to sound as a word. As the word actually is the “ia” is treated as one syllable so the second “a” in the word is effectively the penultimate syllable.