How to do async fuctions?

I dont know what i did, but now it compiles, the thing im trying to do, is use a fuction like a event on BP, where we can put delay fuction and the similar thing that i found is FPlatformProcess::Sleep(500);

And in this image you can see that i am trying to do something like this:

Do you have any suggestion? I´m trying to simulate this, because in the future i´ll need to use something similar to delay in BP.