Help! How do I do two tasks with one Image Button?

Hello, I've started this app inventor 3 days ago and I am having some troubles

I'm making a program where I have to choose the correct picture that the computer randomly chose from the beginning, but I have some troubles which I really need help!!

I'm fine with making the game which is:

  1. If I click on the wrong one, the image will be replaced to a 'x' sign image
  2. If I click the correct answer, the image will be replaced to an 'o' sign image

but then I don't know how to:
3. Make the notifier give an error message when I click the 'o' sign image again.

Screen Shot 2021-01-28 at 8.17.35 PM
(this is what I did before...)

Every time I click on the correct image the first time, the error message pops up with the 'o' sign... :((

How do I make it work independently?

In which event did you put these blocks, and the exact position too..

Sorry for making it too rough :((
I've made that block to all of the blocks I've made!!
From Image 1 ~ 9 (Except 5 because I am not asked to make it function as a button, but to move the correct image into the 5th image (center))
But it didn't work...

U put two task one below the other inside the when button click

I guess this is what happens-
You immediately set the picture to o.png afterwards the if statement is not part of the if-elseif-else block but is a seperate statement.
This is the reason it is being called everytime.

So, just make the notifier part of the if-elseif-else blocks

But then um... I want them to work independently
If I do put two tasks under the other, It works right after the other task

Use to do result block

Like this?!
But then when I set it up like this, there is no way for the notifier to be called :cry:

Any others will help you by what I mean but I am sure to do result block work fine

add this statement
o.png == global imgpick