Events...?

Hi, forum of rpg creators!~

I´m new here, and I wanted to ask something to all of u...

Is related to the events in the RPG Maker VX Ace (engine that i'm using).
I wanna do that when the character step in a space, a even appears. But, here's the problem. The thing that I want to do is this:

Like... I wanna do that when the chara steps over one of those "event squares", say "hello! anyone is in here?", for example. Well, the thing is that I don't know how to "cancel" the others, so that the event doesn't happen again if you steps on the other squares.

I do not know if I explain ... I hope so, hehe

Btw, sorry for my bad english xD Hahahaha
I hope u can understand me~

You can turn on a switch and create a second page for each of those event which has that said switch as condition and no contents at all.

Each Event has Event Pages.You shall use a Switch.

After the character says "Hello!" :
On EVERY Event:

Use Control Switches to set Switch with id 001 to ON. (Name that switch "stepped on event" by the way)
Now got to ALL these Events and create a new Event Page on them.
Set Conditions of the Event page to be that Switch (stepped on event) turned on.

You can also try this. It will probably help you on a lot of thing you wanna do in the future:
https://forums.rpgmakerweb.com/index.php?threads/free-tutorial-game-for-vx-ace-events.29370/

Edit:
Ninjaed.

Create a switch and name it (so that you don't accidentally use it for something else).
Have a second page on each of those scripts which is conditioned by that switch, and which has no commands on it at all.
At the end of your dialogue (on each event) turn that switch on.
All events will move to their second page and none will run again.

EDIT
Double ninja'd

Oh, thank you all! Really ^^ I'm going to try all the alternatives you gave me ~
I'm gonna say which was better when I finished

Thank you very much again!

Ah, hi again, everyone! Jeje
I have a little problem.

I'm really embarrassed to say it... But, 'cause of my low knowledge 'bout how works the engine, in addition to my novice english, I can't really understand what I should do...
I don't ask for a translation. Only, please, could you be a little more graphic with your explanations? As some pictures to guide me in what to do, that would be an impressive help :D

Sorry for the inconvenience I could cause. Thanks ^^

First, I would strongly urge you to stop everything and go through the Events tutorial that Dreadshadow linked to in his post. It's a playable tutorial so interesting to do, and you can also open it up in the editor to see how everything is done. It takes about 3 - 4 hours to complete, and will save you months of time in the long run.

Here are a couple of screen shots. Done with the snipping tool, so a bit blurry, but you should be able to see clearly enough.
And that's it. Have that switch on every event that you want turned off after only one of them has been activated by the player standing on it.