How to add new unit abilities with Lua and how to add new icons to cities

[fsxpilot101]

Forgive me if this is the wrong forum (I just joined, this is my first thread), but I am trying to add the a corporation mod to civ v, and I don't know how to add new unit actions to my executive unit (which spreads the corporation to new cities, I need to add a new action for that) and how to show that the corporation is in the city. All tutorials I have looked at have been no help. If anyone knows, please reply!