Hello!
I was creating Main Menu to my project. Beacuse I don’t how to do this, I used this tutorial LINK
Step 10 is saying: Inside the Graph window, Right-click and add an Event Begin Play node.
But in this Graph I already have onw Event Begin Play.
So, what to do?
Use it 
Events are communication gates between the different elements of your game.
I suggest you follow this series of tutorials
That is the problem. I can’t use it, beacuse something other is connected to it, and it can’t be more.
You can either add things on after what’s already there, being careful to get the order right. Or, you can add a Sequence node that lets you do a bunch of stuff one after the other. It equates to the same thing, but you can use them to clean things up a bit.