When, After, Before Explanation

1. When i saw the tiger, i ran away.
2. When i had seen the tiger, i ran away.

3. After i saw the tiger, i ran away.
4. After i had seen the tiger, i ran away.

5. I had seen the tiger before i ran away.
6. I saw the tiger before i ran away.

which one is correct, which one is wrong?
and what's difference in detail each sentence please?

(y) very thank you

*note: i think all the sentences are acceptable. but i don't know which ones are formal writing please?