how to get a new line in a text

Sometimes using Numbers I need to get a new line... I know numbers should be used for numeric purposes, but sometimes I find it perfect to organize things, but once I can get a new line easily using a character that I'm not able to paste here, it is like a P, but on the other side... now if I use that character, all the cell become blank ...

How can obtain the same result?

thanks a lot