You understand "always" and "never", but just know it isn't always 100% and 0%. These words are often used to exaggerate. For example, "he always gets up late" or "he never does the dishes" - he probably gets up early sometimes and does the dishes sometimes.
For "ever", this is my answer to another question here [www.italki.com/question/280155]:
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"ever" = "at any time"
"never" = "not at any time"
Questions (past):
Did you (n)ever go to Brazil?
Have you (n)ever been to Brazil?
Questions (future):
Will you (n)ever come to Brazil?
The 'future' questions include the past, meaning that this event (coming to Brazil) has probably not happened before. You could add a word like "again" to the end of the sentence if it has happened before and you are asking about whether it will happen again in the future.
To answer questions with "no", we often use "never":
Did you ever...?
No, I never...
Have you ever...?
No, I've never...
Will you ever...?
No, I'll never...
We don't use "ever" unless answering in this way (with a negative):
I don't think I ever...
I'm not sure if I've ever...
I don't know if I'll ever...
So we normally just answer positively with something like "Yes, I did/have/will", "Yes, last month", "Yes, twice", etc.
Similarly, you can say "If you (n)ever come to Brazil..." (past: "If you (n)ever came... / If you have (n)ever come...)
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