An earnest-looking person of indeterminate gender strolls into the classroom. They take up a position at the lectern and clear their throat nervously -- is this the teacher?
"Ah, hello. I'm Morgan, and this is Freeform Roleplaying 101. Now, this is actually an example of roleplaying in progress--" Morgan points to the first paragraph above, which has magically appeared on a chalkboard. "See here, where I walked in, that's what we call third person present tense narration. Third person narration is the standard for freeform RP."
"That means you write about your character as if you were observing them, using their name, and pronouns like 'he' or 'she.' Present tense just means you write about this character as if things are currently happening -- 'Morgan walks,' instead of 'Morgan walked.' Everyone with me so far?" Morgan looks around. Of course, nobody's paying much attention.
"...right. Anyway, you can also use dialog in freeform RP, which of course I'm doing a lot of, here. You should put quotation marks around your dialog, and use a tag like 'Morgan says' occasionally, to remind the other players who's talking."
"Now, I'll need a volunteer from the class for the next section," says Morgan.