How to activate the rewrite mod

[Faraday]

Hi, I am sorry I am french and I do not speak english very well.
So I started to creat a web site with Wordpress ans a localhost : Xampp
When I want to change the permalinks in the Wordpress board, all my pages have error 404.
I want to change this one : http://localhost/Projet%20boudeuse/?p=123 into this one http://localhost/Projet%20boudeuse/exemple-article/
And I don't know why I have error 404 everywhere, on all my pages when I make that change.
I read on the internet that it might be the rewrite mod being not activated but I don't know how to check. I don't know where I need to go into xampp to find the rewrite mod nor the way to active him.
I found nothing in the french forum so you are my last hope to do something. And if someone ansewering me can please explaint it with very simple word because I am a newbie with computer and all that stuff is very complicated to me
Thanks a lot the people who will save me.

[Nobbie]

And I don't know why I have error 404 everywhere, on all my pages when I make that change.

Simply your change is faulty and results in faulty URL. You did an error.

I read on the internet that it might be the rewrite mod being not activated but I don't know how to check.

Nonsense. You would receive an error 500 if rewrite mod is not activated.

[Faraday]

I think I might put a space between two words in my web site name. Do you think it can come from that ? Thank you for your answer. Do you know how I can remove it ?

[Nobbie]

Maybe.