I think he is referring to the Inferno spell from Diablo. That is pretty complicated if you can't make basic spells.
If you consider you suck at spell making, you can start practicing with simple spells like an AoE Sleep. Have all units in an Area of Effect be affected by a Sleep spell. Then you can go to a little bit more advanced and so on. Advancing from very very simple spells to more complicated is the key. All of us started like this, or atleast I did.
If you know how to make moderate spells (give me an example of the most complicated spell you made) then I will tell you how to make it but unless you do, it is useless since you need more experience. Don't worry though, you can learn.
~Daelin