you will need blank DVD-/+R's. Good DVD-/+ media is Taiyo Yuden, RiData, TDK, Sony, Maxell, or Verbatim or Fuji.
Also, a quick note about DVD media, if it says 'Made in Japan', get it, u can't go wrong 95% of the time with Made in Japan DVD's.
Just make sure u dont get any fakes. Good sites to buy from are newegg.com, rima.com, supermediastore.com and meritline.com.
1.First, open DVD Decrypter. Go to mode, then select ISO, then select write.
2.Next, browse to the PS2 game's image u have and select it.
3.Now u can choose what speed to burn at, always burn less than 4X, and if you're using DVD+R's, then if you're DVD burner supports it, booktype it to DVD-ROM, just select the option next to the write speed.
4.Next, make sure everything's in place and select write. Then it'll start to write automatically by itself.