How to burn .iso file?

I'm not very clever with computer stuff, and obviously I need help. Well, I've downloaded an OS iso file, and practically I don't know what to do with it. I tried burning the iso file onto DVD+R but I kept getting error message that says "False media type". I was wondering if had used the wrong DVD types? Plus, I'm thinking of using freeware iso burner as I just want to burn that only one particular iso file. So, any help, please. Thanks in advance.