Reply to Re-edits

Hi everyone! I fairly new to the whole producing thing so please bear with me if I ask any stupid questions.

I'm wondering how I would go about doing a re edit of a track?
I constantly hear tracks that the DJ has re edited to give it that bit of their own touch. Some times it maybe be subtle changes, but sometimes it's almost a completley different track. I've had a good look on YouTube and not really come across anything helpful.

thanks Paul