Okay, everything's almost set before I start making the campaign. What I need is to make the nexus produce another unit other than the probe.

I want the nexus to produce:
> Zealot Fenix
> Dragoon Fenix

Also, I kinda want them to have the cybernetics core as a prerequisite before they can actually be trained.

Since the photon cannon and shield battery is gone, I thought of adding this to make things a bit more fair for the protoss.

In firegraft in the Button Sets tab find the Nexus command card (ID 43).
At the bottom of the properties list, right above "Used By" is an Add dropdown. Click that and select Train Unit to bring up a list of units.
Find the first unit you'd like the Nexus to train and hit Ok.
Next it asks for the button position. You can put it wherever. The buttons go in order left to right, top to bottom. (top row 1 2 3, mid row 4 5 6, bottom row 7 8 9).
You'll need to set strings for the tooltips on the buttons, but you can either add them first or just use placeholders and do them later. 'Disabled' is shown when the requirements to build the unit are not met and 'Enabled' is when they are.
[attach=9416]
I just used the dragoon ones as placeholders ... I'm not sure if anything bad happens if 'None' is selected and you don't have the requirements met for the button.

Now you have your buttons, you need to set Dat Requirements. So go to that tab.
Find and select your first Fenix (77 and 78, same as unit ID I guess) and check the 'Used' button.
Right click the '==End of List==' and hit Add Item, three times (so you have three 'None's).
Select the first 'None' and at the bottom select Opcode, and from the dropdown list choose 'Current unit is ...'.
Select the second 'None' and select Parameter, and from the dropdown choose Nexus (Press N until you find it if you don't want to search).
On the final 'None' select Parameter, and find Cybernetics Core.
Repeat this for your second Fenix.
[attach=9417]
The "Current unit is ... Nexus" says that only the Nexus can train the unit, and the "Cybernetics Core" by itself means you need that building as a requirement.

Now your nexus should be able to train both fenixes.

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