Can i get 16 abilities on one hero?

Well i have seen abilities when you click them it brings you to a new set of abilities, that what i want to try and do. Make a four groups of a spells, and one link to each set of four. Is This possible? They need to be able to level up. Im really lost on how to do this any help would be appreaciated.

Yes. Use the Spellbook ability

Yes, spellbook ability is the thing used to get multiple spells in one. It is an ability (as such, it can be an item ability, unit ability, hero ability) that opens up a new window, holding other abilities. The trick is, you can't level these individualy. As I said, the spellbook itself is just an ability, so you can level up the spellbook as a whole, but you can't freely pick spells from the spellbook to be learned; they are a package deal.

This gives you basicaly two options, either you make the spellbook contain more and more spells as it levels up, or it has multiple spells from the begining and then it gets better versions of them (or a mixture of these two concepts, or you can even add comepletely different spells to each level; that would be wierd, though :/ )

Spellbook has one more nice characteristic: you can alter it's ordercode, allowing a unit to be able to have multiple abilities based on spellbook.

Maybe you could store the heroe's (exp/lvl) in an integer, and when he reaches a certain (level/amout of exp), you could have another spellbook filled with the level 2 spells? (removing the original spellbook and replacing it with the new one?)
If anyone has played the new, HUGE notd, the abilities in the spellbook level up...

but thats the thing... you can make a spell book a hero ability, set the require level and set the spacing between leveling upgrades...

and also for each level, you can choose which spells are in there, that way for a lvl 1 spellbook you can have rain of fire and fire bolt and then for a level 5 one could have flame strike and phonex.

Here is a map were the spell book is used + the inventory. That may help you.