Translation:They finish school at 5 today.
The word the makes it sound like you're talking about the building and not the activity. They finish school sounds like doing the activity, but saying they finish the school makes it sound like they finished doing something to the building.
Could this be translated as "finished studying" as well, or no? Maybe my idea of the word 学 is messed up.
in this case, 学 is used to mean school, rather than learn. 放 means "release", so it's literally "released from school".
学 can also be a verb - to learn, to study. It just doesn't take that meaning here.
Sometimes "released" is right, sometimes "finished" is right. Pick one or the other or both Duo and stick to it.
If the speaker says this earlier than the time, it should have a 'future' nuance like 'they are going to finish' or 'they will'. The future nuance translation should not be "wrong". Some sentences accept future nuance (I don't say 'future tense' because both 'will' an 'is going to' are grammatically present tense: English does not have real 'future tense'), while some sentences do not --- quite inconsistent, while Chinese sentences only show 'time words' like today and tomorrow without any verb marker (conjugation) other than 了, I guess....
I translated it as "they end school at 5 today" and i thought it should be correct since "end" and "finish" are both grammatically correct and they both are similar in meaning.