I'm on the first scenario, with the enemies coming through on the road, where you have to raise a secret army and guerilla fighters.

I cannot for the life of me figure out how to do this. There isn't a button anywhere that says "RAISE SECRET ARMY," nor have I found any information in the FAQs and/or other guides. The mere fact that nobody else has mentioned this on the forums leads me to believe I'm a blundering fool.. but any enlightenment is good enlightenment. And if I cannot figure out the controls for this basic play element....

Try clicking on the city with the flying dollars above it. That should get you going :=)

Every turn of the games consists of phases.
Guerilla phase*
Combat phase
Revenue phase*
Disclose phase*

to finish phase you need to press 'end phase' button.
phases marked by (*) can absent since for example you have no countries to disclose, or there was enemy's invasion to rise guerilla.

To rise guerilla, disclose country or collect revenue you need to click on this country in proper game phase. Such countries are highlighted by red or green circles.

You have to finish your Movement and Combat Phase then press "End Phase" and go to Recruitment Phase, if there are any countries with Revenue; if there are no such Revenue-giving countries - you will be automatically brought to "Disclosure" Phase, where you should click on your SECRET ALLY country (marked with folded flag) and deploy the units.