How Can I make event of this?
You can try using events to show/hide layers.
Put the pop up content on a “popup” layer and then set the events to show or hide it before changing the scene.
Actually I am a noob at gdevolop. I didnt understand … sorry… and thanks for suggetion…Can you tell me how can I make the next level comands…I know about change the scene but its not made my work
No worries, I’m still kind of a noob lol, check out this wiki page for more about using layers
http://wiki.compilgames.net/doku.php/gdevelop5/interface/scene-editor#layers_editor
As for changing to the next level, you have to either…
a) Add conditions and actions in the event sheets - for example:
Condition: Player object collides with another object
Action: Change scene to “name of scene”
b) Use text or sprites as buttons - create the objects for that and then in your events…
Conditions: Mouse > Left key press > Cursor touch is on an object
Action: Change scene to “name of scene”
I’m sure there are other ways, but those are the ones I use in my game. 
There are a few examples around on the wiki so you can see how some things are done.
Oh wait, you already have some buttons.
Go to your event sheet and do the second thing I described. Here’s a screenshot of one menu item from my game. For yours, you can do something like it in your events - change the object and scene name.
I have 8 scene …
Menu + Level 1 + Level 2 + Level 3 + Level 4 + Level 5 + Game Over + Middle (My picture of this post) = Total 8
My Event of scene Menu
→ Player is collusion with Play Button = Change the scene “Level1”
My Event of scene Level 1,2,3,4,5
→ Player is collusion with enemy = Change the scene “Game over”
→ Player is collusion with End = Change the scene “Middle”
My Event of scene Game over
→ Player is collusion with Game over text = Change the scene “Menu”
My Event of scene Middle (Suppose)
→ Player is collusion with Home Button = Change the scene “Menu”
→ Player is collusion with Next Button = Change the scene "Level 2 " …(#Mark 1)
→ Player is collusion with Retry Button = Change the scene “Level 1”…(#Mark 2)
Now think about (#Mark 1) if I complete level 2 it will bring me the scene (Middle) and if I click on next button It will bring me to scene level 2 again instead of Level 3
Now think about (#Mark 2) if I complete level 2 it will bring me the scene (Middle) and if I click on Retry button It will bring me to scene level 1 again instead of retry the Level 2