Enter function using keypad

I'm able to do that, but I want to make an enter button instead of just typing a number and then the code automatically does stuff. I want it so that when the # key is pressed, it analyzes what's displayed on the LCD (preferably multiple characters), then plays a song based on the set on characters

I can key a certain key to do certain things but I want it so that the enter keys looks at what's displayed and does stuff based on the characters displayed

That's why the * button works as a clear display button but not the # button as an enter button, but I can't figure out why