Now, there are advantages to both. However, speaking from experience.
I prefer the second as this game is all about flow, but the former is the easiest and quickest. It's quicker to just say, "ooc Examine the item." or "ooc just do COMMAND." But does it teach and reinforce a method.
My guide here is to help you to not do that. To keep it IC, and to help visualize and contextualize the struggle that is teaching with purely IC methods. Offer advice, and make clear the techniques of teaching ICly, as well as where there's pitfalls to avoid.
First off, the core disadvantage of simply providing the information in local ooc is that it very quickly exits the mind of the student. Unless they have to do something to translate that knowledge into actual memory. All telling them and them doing it once is going to do is make them quickly forget and not gain the knowledge they need.
So... make a scene of it. With the following three techniques.
All of these techniques are designed for specific cases that occur after someone asks something in looc.
First a series of questions that you should ask yourself in this situation.
Does your character know about this thing? Would they know about it? Have they been taught about it in character in the past?
These are questions that should be addressed first, because half of this game is having the maturity to say no. Even when you IRL don't want too.
If these questions are answered no, option one, is what I call specific direction. It's where you point them to someone who might know.
JaneBaka says, "I really like this new liteterm, but I can't really seem to figure out how to make it work."
[OOC: JaneBaka says, "Yowzahs how's this grid editing I've heard about work?" ]
Now you could stop here and offer a tutorial on the grid, editing nodes, the relevant help files, all that jazz, because you're an experienced player who's done it all before. Or... You can interrupt that thought process, and choose the more themely path. Maybe you're a solo who has knives for fingers. And shouts real loud at the noise boxes around him. Does that sound like someone who'd know all about the grid?
So, the first technique is the interrupt. It goes something like this.
[OOC: JoeBaka says, "Yo, that's something to be figured out ICly. So Joe's gonna treat it as an IC question."]
JoeBaka says, "I look like a fucking nerd? Why don't you ask a fucking nerd like Buttonman about that?"
You take the question, you twist it, and address it partially out of character, and then get them started in character with a hook.
The second technique is all about approach. where you act as an agent to approach another person or the person themselves, and have them or you begin to educate the student, this can be done through many methods. SIC is common, maybe you know a nerd like said Buttonman.