After traits are assigned, which are inate abilities and capabilities, we move on to skills, which are learned abilities and capabilities. In many cases, if you don't have the appropriate skill, a GM can allow you to make an appropriate trait check with a penalty to attempt to use the skill anyway, but that's the GM's call as to whether or not that makes sense in the specific given situation where he's calling for the check.
Each skill is meant to be fairly broad, so that rather than having a very long skill list, a shorter skill list covers more eventualities. However, given that this system is, by design, a rules-light system, that means that there will be a fair bit of GM interpretation as to what skills will actually allow you to do on some of the less obvious cases; it's not my intention to proscriptively spell out uses for skills, only to describe them briefly.
The skills available are, then:
Climb: Self explanatory, really, right? Without taking the skill, you could attempt this with a Strength check with a -2 to your roll.
Drive (when applicable): Mostly refers to settings in which self-powered land vehicles (i.e., cars and whatnot) are available, but could also be used to refer to driving a coach, carriage, or wagon, if needed.
Fight: The ability to skillfully engage in melee combat, either with or without weapons. For characters who don't take this skill, you can still attempt to fight using Agility with a -2 to your roll.
Heal: The ability to do both immediate first aid, as well as long-term care, assuming appropriate supplies are on hand. This can save the life of a character with an improvised field dressing, or even with long term care, possibly remove major diseases, injuries or insanity. The GM is the final arbiter on whether or not something can be healed in the first place.
Knowledge Specialty: While the Knowledge trait can be used as a general check to find out if a character knows something, characters with more specific knowledge, such as Knowledge (Occult) or Knowledge (Engineering) can determine things that are beyond the Pale for general Knowledge rolls and make knowledge rolls that other characters cannot. Before spending points on this skill, I recommend talking with your GM to make sure that it will actually come up in game. You can take this skill multiple times, with different specialties each time. If your specialties are in turn fairly broad, the GM might give you a penalty to certain rolls, although you'll be able to roll in more situations. Again, talk with your GM to make sure you understand the implications of the tradeoff.
Persuasion: The ability to lie, bluff, persuade, convince, and even "pick up" characters romantically are all covered by this ability. Many of these applications can be done with a charisma check, but certain of them (especially bluffing) will receive a penalty without using the specific skill.
Piloting (if applicable:) Mostly used for operating flying vehicles like airplanes, helicopters, spaceships, blimps, or whatever. Can also be used for boats, if wanted. Make sure that your setting has a use for this skill before you take it. Most fantasy settings, for example, would not.
Repair (if applicable): The ability to fix gadgets, machines, and other complex devices. Only applicable in settings where machines are common.
Riding: The ability to mount and handle a riding animal. Even unskilled riders can usually make an attempt with an agility check (or a charisma check if the animal needs to be convinced to let you--or both, depending on the circumstances) but this is a relatively specialized skill, so you'll be looking at anywhere from a -2 to a -4 penalty on those rolls.
Shooting: The ability to handle any weapon that shoots a beam or projectile. While this is more important in modern, semi-modern or futuristic settings than in others, where powerful firearms are more commonplace, it also is the skill used for things as simple as a slingshot or bow and arrow too. Agility checks at a -2 (or more, depending on the complexity of the weapon being used) can substitute.
Survival: The ability to take care of your needs while away from civilization. Want to catch animals and fish? Find edible plants? Follow the trail of a wanted man? Start a fire with just a rock and a stick? All applications of the Survival skill. Some of these applications (but not all) can be attempted with a Perception trait check at a -2 (or more.)
Swim: It's amazing to me that there are people in this world who aren't nearly as comfortable swimming as they are walking or running, but apparently its true. Is your character capable of crossing the river? Keeping himself afloat if cast overboard into the ocean? Even untrained swimmers can attempt to doggy-paddle with a Strength check, but you'll be doing it at a -2 penalty at best.
Throw: Used for anything that you toss. Atlatls, slings, darts, Molotov cocktails, grenades, or water balloons and snowballs; they all apply. Agility checks can sub at a -2 (or more, for more complicated types of weapons or manuevers.)
While this list isn't meant to be exhaustive, between it and the traits, your GM shouldn't have any trouble figuring out something to have you roll for any action you tell him you want to attempt. And that's the whole purpose; to give a quick and dirty tool that GMs can use to keep the game rolling quickly and without fuss, and without the need to resort to looking something up, or wrangling about what rules mean. This isn't meant to be a comprehensive system as is; it needs GM adjudication to work.
You assign your ranks in skills by assigning the following ranks to whichever skills best fit your character. For non-modern settings, you can assign a d12, d10, d8, d8, d6 and d6 to whichever of the ten skills you wish. If you're adding back in Drive, Pilot and Repair, add an additional d8 and d6 to that list. Anything else that you don't possess, you can either sub a trait check with the appropriate penalty, or use a d4, whichever is better (subject to GM approval.)
If that doesn't seem like a lot; don't worry---there will also be forthcoming rules on advancing your character. These initial chargen rules gives us the equivalent of neophyte, "low level" characters, so they're not meant to be extremely capable across a wide spectrum of situations. Rather, they can have a few things that they are good at, and a few others that they are decently capable at, and they can start there.
Coming next: the types of die rolls you make in Anti-d20, or "Running the game" followed shortly by Advancing your character. After that, we'll have a look at a few slightly more specialized rules for specific campaigns, and then move on from there.