Was ist der Unterschied zwischen If it stop raining, I will go for for a walk. und if it stopped raining, I would go for a walk ?Du kannst auch einfach Beispielsätze geben.

You must take a look at "IF clauses".

The first is correct. It is a possible situation in the future. But the last one is wrong, it must be:

"If it had stopped raining, I would've gone for a walk."

This is in the third conditional, an imaginary situation that didn't happen. It's a little complex but once you get it it'll be a lot easier.

If you haven't studied the perfect tenses I would recommend you to take a look at them first to understand it.

Summary: the first is a possible situation in the future, the second is an imaginary situation that didn't happen.