How to turn the front screen on my phone on?

I have a Tracfone-branded LG420G and I can’t find anywhere how to keep the front screen on the outside of the clamshell always on. The phone proper’s user manual doesn’t come with the tracfone paperwerk and there’s nothing directly indicating in the menus on the phone how to manipulate the screen. When the battery dies or when I mess with the alarm, it will stay on, or it will start turning off. It’s driving me quite insane.