Like Donay said, it will depend a great deal on context. Se here's some context:
You are talking to a friend at lunch. She knows you like art, and she had read the night before about an art exhibit that is going on in the local museum. She assumes you have already heard or read about the same exhibit. She's introducing the topic for the first time. So, she asks:
"Have you gone to the new art exhibit at the museum?"
EXPLANATION: She uses the present perfect to ask about a past life experience you had or didn't, with no specific time reference. In Portuguese, she would ask using the past simple, "Você já foi para a exibição de arte no museu?"
You answer in the negative:
"No. I read about it but I haven't gone yet. I think I'll go tomorrow afternoon."
EXPLANATION: you use the present perfect again to talk about a past experience you had or did not, with no specific time reference. In Portuguese you would use the past simple, "Não. Eu li a respeito, mas eu não fui ainda. Acho que vou amanhã de tarde."
MORE CONTEXT: You go out with your friend a couple of days later for dinner. She asks you:
"So, did you go to the exhibit?"
EXPLANATION: she uses the past simple. The topic had already been introduced a few days before and the specific time referenced, at least in her mind - "yesterday or the day before". In Portuguese you also use the past simple, "Então, você já foi para a exibição?" You answer:
"No, I didn't go yet. I didn't have time. Something came up at work."
EXPLANATION: you can use the past simple for the same reason. The topic had already been introduced and the time period has been established. In Portuguese, "Não, não fui ainda. Não tive tempo. Surgiu alguma coisa no trabalho."
This is a very subtle contextual difference between present perfect and past simple. It is complicated more because in Portuguese you use the same simple past tense for both moments in the conversation. Will you be misunderstood if you use only the past simple in English? No. But the subtlety will be lost from the context.
Long story short: asking and talking about past life experiences with no time reference, especially when introducing the topic for the first time, use can the present perfect. Once the topic has been introduced and a time reference established (even if it is only in the speakers' minds), you can use past simple.
I'm sure there's tons about this on English Experts, so make sure you check it out here!
Hope this helps!