Good Morning.
You can create a (Layout), to load the game, indicate it as the first Layout, in the (loader Style) option leave none.
On the Event sheet, enter the code:
System: On loader layout complete - System: Wait 0.5 seconds
- System: Go to layout 2
So your game will show your loading screen, and after the browser loads all the objects will wait 0.5 seconds and advance to the next screen.