copying extracted rar files, and then playing on dvd

Hi everyone. I really need some help, being new to copying files onto dvd. I'm downloading via grabit rar files and have eventually worked out how to extract them. however it's never easy and i have now gone out and bought blank dvd's to copy my downloads, which by the way are playing fine on the pc.
My problem is that I'm unsure how to copy onto dvd. I'm in the process of downloading nero 7, but need some help.
I've tried to copy twice onto dvd but they don't work in our normal domestic players, it merely flashing up with two squares boxes.
Can someboby please help, I'm going mad slowly. Gregg

 

I have checked and the files I'm trying to put onto dvd are iso's

 

Thanks just tried it and has worked first time, cheers Gregg