Replying to Your gopro editing knowledge is welcome in here

I'm gunna film this weekend with a gopro that isn't mine and we basically just need to do some simple editing, maybe put some text and music over the video, which would be the best software to do this, and preferably it is free and i can download it on my computer cause we have to do this soon.  Thanks! +k for good response.  btw i put this in media and arts too but i figured it'll get more attention here and i  need an answer rather quickly