Often, you will want, or need, to know something about the world. The GM should tell you the relevant information that your character would know offhand, or be able to easily observe.

But sometimes, you don't know something. The first thing to do is to ask, GMs are humans and forget to mention things, and other times may assume you know background information that you don't. Sometimes you just forget, and the GM should just tell you.

When that fails, you can gather information.

Flipping things around

Competence recognizes both competence and incomptence in other people. Aka, to be good at something means you also can tell when others are good at it, if you spot them trying it. This is shorthanded to doing the action 'backwards'. All your actions can be used 'backwards' to gather information.

Let's start with perhaps least useful backwards actions, the Body actions. All of those can be useful, but only in very specific circumstances.

• Grasp would let you check to see how difficult a pickpocketing a specific person is going to be, or use your skill at safecracking to recognize how hard the safe will be to open. It also can allow you to notice if anyone else is pickpocketing, although that basically requires them to do it in front of you.
• Sneak lets you see where you could hide in an area. And, because you know where people could be hiding, you could spot someone hiding there. Although, again, this would require them to be doing it as you looked.
• Assault lets you locate things you could use in a fight, and when used against people, can be used to see if they are carrying concealed weapons or holding themselves as trained combatants, perhaps even scanning the room for threats just like you are.

You can also do Modify, Grift, and Order backwards. These three are much more useful.

• Modify would be to see if something has been tampered with. This is very useful for hacking, if you are trying to track down what another hacker did.
• Grift would be to try to figure out if someone was lying, although again they'd have to be lying at the time. It also could possibly detect if they are playing a role in some manner, even if not lying, if their outfit is just slightly wrong or their word choice isn't quite correct. Maybe even scan a room for people out of place.
• Order would be figuring out if someone was the legitmate authority, or who the legitimate authority would be. It also can be used to figure out what authority people expect, or who people are deferring to in a room.

The main actions

The remaining three actions are what you you would normally use to gather information, and you use them forward, not backwards.

• Locate is the biggest one, the action is almost entirely gathering information, and can be used to do everything above, and try to track down everything else. You just look at the world around you, and notice things. So in that sense, it's a very powerful action, but it does only give you information.
• Connect is basically just asking other people for the information. Sometimes directly, sometimes asking around on the DL, and sometimes tracking them down though a friend of a friend of a friend and getting them to spill secrets over a beer. Remember, you can do this in a flashback if it doesn't fit in the present.
• Understand is the odd one out. You generally can't use it forwards to gather information to start with if you have nothing, you use it when some aspect of the team gathering information fails, and you have gaps in your knowledge. It allows you to make deductions about what is going on anyway. You base these deductions off human nature and a very wide understanding of the world. It's basically the 'genius' archtypical behavior, where you just have 'figured things out' despite not really enough information.

For an example of how all these work, let's see how Sherlock Holmes would gather information:

Sherlock investigating Sir Reginald Westbridge, so he uses Connect to ask the Baker Street Irregulars when he's been recently. The Irregulars say he's been see frequenting a lot of different bars recently, a wider variety of bars than normally expected, although he doesn't seem to be a drunkard. Sherlock then uses Locate to look at at Reginald, and notices he has a very cheap cufflinks despite otherwise having expensive clothing and being well off, and that he has a specific color of dirt on their shoe. And finally, Sherlock uses Understand to put that information together, realizes that the dirt is from Stepney, a very poor district, which is hardly somewhere that a person like Reginald should be, and realize that Reginald might have pawned his cufflinks, which, when combined with the excessive visits to multiple bars, might indicate a gambling problem he's hiding.

And...that is a lot of leaps of logic. This deduction is not something that a person in real life could do, and in reality there's dozens of reasons that the observed things could be true. Sometimes dirt is just dirt, and his good cufflinks got misplaced and he grabbed a pair without noticing, and he's going to bars because he's had a split with his girlfriend, who turned out to be friends with all his other friends who chose her over him, and he's been barhopping to try to meet new people, while carefully avoiding falling into alcoholism.

However, this is fiction, and just how our cat burglars can fit in vents that in reality about four inches across, our geniuses can deduce things like this. Sometimes the conclusion may not be entirely true, but the fact the detail was included in the story means it is relevant, and Sherlock can move forward on the assumptions he's made. Because the story won't be 'dirt is dirt and the cufflinks got misplaced'. Even an incorrect result will be that Sherlock is 90% right, but Reginald is actually covering for his brother's gambling addiction and trying to get him out of those bars.

That's what happens when you use Understanding. Even if you don't get the full picture, you'll get something that the GM wants you to conclude...maybe not true, but it will lead you to true things if you follow the conclusions.

You can also use these three Actions backwards just like the other Actions, to determine if someone else is good at that thing. Although it could be fairly hard to observe them doing any of them. But if, for example, you watching someone playing a game of chess, you can use Understand to figure out how good they are. You can watch them socalize and see how well they Connect. Or watch them Locate something and see if they can find it.