In the science.ini you have to change the name of the spell, which you want to replace into the name you want.
Science SCIENCE_forKingThranduil
[...]
End
And you have to change other spells, which need your spell for beeing able to buy, the old name into you name you want.
For example:
Science SCIENCE_Anduril
PrerequisiteSciences = SCIENCE_GOOD OR SCIENCE_MEN SCIENCE_Heal
SciencePurchasePointCost = 7 ;GOOD_RANK_2_COST
SciencePurchasePointCostMP = 7 ;10
IsGrantable = Yes
End
If you want to change the spell Heal you have to change by all other Spells, like Anduril in line "PrerequisiteSciences "SCIENCE_Heal" to for example "SCIENCE_ForKingThranduil" , but the thame name you have already chosen.
Then you look for a spell, which is alike your spell, you want to do. For example the LoneTowerSpell, which is a summon of a structure, too.
You have to look the alike spell in the files, I have already written and in the objectcreatiolinst.ini ,because you have a summon.
After that you can do your own spell, with new Commandbuttons.
At the end you have to change the Commandset of the Spellbook and there you replace the Commandbutton of the old spell with the new Commandbutton of your own spell.