RPG MAKER VX: How do I make a an event only happen if a certain event has passed?

I need to make a certain event happen, but only when another event somewhere else has already passed.

This means I need to make an event in one room when you go into it, and then when you go into a different room, another event plays. Then, when you go back into the first room, a different event plays, so the story makes sense.

I apologise if I should know this or it's obvious, but I worked out most of the things I needed to know myself. I have a feeling this is something to do with variables, which I don't know much about.

Please help!!!
I am inspired but I can't make anything very easily without knowing this!!!

Thanks, =D

 

i've never used THIS particular version of RPG Maker before but i HAVE used other versions. if it's anything like the other ones, you have to use a "Switch" or sometimes called "Flag". after the end of an event you add a piece to turn ON a switch. then when you make the next event make it so that it will only happen when that particular switch is ON. you can also use the switches to make sure that events don't repeat itself everytime you go there by adding no event with that particular switch when it is ON. hope that helps even tho i never used that RPG maker before, the concept should be the same but i don't know what stuff is called in that version or where to find the info.