Hello,
everytime i place the simple formula
Set(MyVar, "Hello Power Apps")
into the OnVisible property of a screen it gives two error messages

1. Error:
the first opening Parantheses says: invalid number of arguments: recieved 1, expected 2
This error prevails no matter what i type as the second argument.
2. Error:
the comma to seperate the arguments says: The formula contains "Error" when "ParenClose" is expected.
I suppose the error is very simple and due to my limited experience.
Hope someone can help. Thanks and bye.