How to delete a user function and one more question

[Skfir]

Hello everybody! I have just gotten my very-first calculator and it is HP Prime. I have been learning how to use it and I created a function, which I don't really need. It is in the toolbox now, but how to delete it?

Is there a way to get an expression into parentheses easily? Because now I need to press the () button at the end of an expression, then delete (, then move cursor to the beginning of the expression, press () again and remove ). So is there a quicker way?

Thank you guys!