Well, This may be confusing to those used to Roleplays in single threads, like those on The New Twilight Saga.
So, to start a section of RP, make something in the right area.
Like if you're at the school and you're a scientist, you might make a thread called 'Itex Lab: Devision of New Research' Or wherever.
And if you're in the flock, you might right a section in the USA area called 'Rocky Mts. Colorado' and anything that happens there will Be roleplayed. If you make a sudden change in the plot, maybe say something above your roleplay with on OOC: before your message.
An example might be;
OOC: Okay, I'm gonna skip to the next day.
*Character name*:
*Roleplay post*