Help me make system skill like invoker at Dota

[KazutoKirigaya]

please help me make a skill system like invoker in dota

example
i have 3 skill ( A, B, C ) and 1 skill to invoke (D)
if i click A, B, C than i click D
it will make skill example wind walk
if i C, B, B than D
it will make skill Warstomp
and more combination like that

but i only can have 2 skill from that invoke

if you play dota, you will understand....

please help me...

 

[Almia]

http://www.hiveworkshop.com/forums/...f4c9d081ed80aadb0da7b9eca&dateline=1368702061