ok.......you want a 3X3 Grid puzzle.......ok then:
1.First make an event, make it touched by hero, below hero. Put inside "Switch Operations" and make a switch called "Grid ON 1" or how you want to name it. Here's how it looks:
2.Now make a new page in the same event, make the preconditions if switch "Grid ON 1" is on. Put inside "Switch Operations" and turn it off.
Now you can copy and paste the event and just change the switch "Grid ON 1" to "Grid ON 2" and so on...
Here it should look like:
Note: You must put some of them already on.
3. Now that you got the puzzle, lets put the Checker....Make a new event, now put "Conditional Branch" if switch "Grid ON 1" is on, then inside of it put another "Conditional Branch" if switch Grid ON 2 is on, ect. Example:
Now then put the switch if all of the switch is on, the door will open (with a switch, demonstrated on pic above)
and there you go, this will check if all of the switch is on, the door will open and it should look like this:
If your still confuse, feel free to ask.