There are loads of Answers to your Question if you do a search.....
This is for your own copy!!----put an Original DVd movie into your DVDrom drive & open Decryptor..chose "Mode"> File, then chose a folder to rip to...Once it's ripped you then chose Shrink n Re-Author.....
If you already got an ISO file the correct size, just open Decryptor n chose "Mode" ISO-Write n it will chose
NERO or what ever you use for burning..can't be simpler than that!
use a bit of common sence n do a search..GOOD LUCK.