Speaking of Broken Earth...
 

Now that I'm going to actually be using it, I notice two of the "community" edges (these are particular traits of a community, not something attached to a chracter) allow the PCs to learn two skills with an advance rather than one, one only Knowledges, one general. I'm pretty sure the easiest way to do this is to have a couple of false "edges" that refund their own cost or pieces of "equipment" that do what I need; however, I'm not entirely clear on how to produce that result. Anyone care to enlighten me?

You can set the number of Advancement slots that an Edge takes up. Just set it to 0 for those.

Yes, but how do I tell it to give the character an extra skill--and only skill--Advance?

You are too vague in what you are asking. Do you mean that the Edge gives a one-time benefit, or do you mean that it occurs every single time that someone wants to "learn a new skill" or "increase lesser skill" as an Advance? There is a distinction between character creation and Advances, even though it is rather clumsy at times within Hero Lab. Edges can be "creation only" but otherwise an object has no idea if it was taken at creation or as an Advance, which is a bug in my opinion -- it is most evident when you want an Edge to bootstrap a new skill.

Since I have no idea what you want, I will guess and give some options:

1) have it give a half an Advance when the Edge is taken. This is only valid if the Edge can be taken as an Advance.

2) have it give half a skill point when the Edge is taken if this is a Creation-Only Edge. This limits it to skills, too.

3) have it give back half an Advance afterwards. I did this with my "Free Attributes per Rank" mod. The player adds the additional skill and a mechanic counts the "lesser skills" or "new skills" and refunds a point.

Based on what you are saying, probably both 1 and 2, since, again, Hero Lab is clueless about when you take an Edge.

Let me quote the two community "edges" (they're really things you get when you do certain improvements to the PC's community, since community building is part of the game) so what I'm looking at is clear.

"Computerized Library
This represents a wealth of digital information that
characters can access through a computer interface.
Community Benefit: Economy and Morale both
increase by one die type.
PC Benefit: When PCs Advance, they can take two
new Knowledge skills for a single Advance. "

and (I'd actually misremembered this one, as its more specific than I thought):

"Public School
Requires: Books or Computerized Library, 12 Build, 12
weeks
This is a public space for learning. All in the community
are welcome, though there is a particular emphasis on
educating young people.
Community Benefit: Once each year the community
can add one new Citizen Edge without needing to recruit
anybody.
PC Benefit: When they take an Advance, PCs may
choose to learn two new skills at d4 instead of the normal
one."

A non-working option is to make up an Advance that requires the Edge. But that does not work because Advances cannot have requirements. Too bad for us since that would be ideal for this situation.

You could make an Edge for Public School with an eval script that looks for the New Skill Advance. If it finds at least one then it gives another half of an Advance to the character. If this Edge can exist more than once on the same character (it does not look like it can) then it would be better with a mechanic that counts both the number of times this edge is taken and the number of "new skill" Advances.

The Computerized Library could look for two New Skills that are Knowledge skill, at which point it can give the 0.5 Advance refund. This way they only get the benefit if it is two Knowledge skills and you do not have to mess with bootstrapping.

I think the important thing to note here is that these are not Edges at all. More like benefits for a Group or Faction, so they wouldn't need to do what an Edge does, in that sense, or cost an Edge or Advance or the like. So it's probably better not to call these Edges at all because that can imply a certain mechanic/methodology within Hero Lab. Although you may still be able to use a Group or Faction to handle these it seems to me this is another situation where we could use another class of "Abilities" for things that just aren't Edges or Hindrances but could potentially use the available coding sections of those things to just do whatever other stuff we a particular setting might need.

Edges are the easiest way to add something to a character. They are not REAL edges. Since you can only have one Group and one Faction I would recommend against using those, especially for a one-time addition.

Edges really are the best way within the framework of Hero Lab. A reward would also work, but then you have to jump into Creation Mode and that is against the point of an Advance.

What I do in the case of 0-cost and 0.5 cost edges is that I make it obvious in its name. "0 - Public School" and "0 - Computerized Library" would do it. This way people know that it is not REALLY an Edge. If you put 0 in the cost it really is free.

Ouch.
Well, I'd create a new type of Advance for each of these. Take the standard advance that adds a new Skill and make it cost half an advance like raising a lesser Skill. You'll want to add a source tag so it only shows up in your Setting.