Motorola Moto G — No Hello Moto

Hi, had a Samsung Galaxy J7 (Android) with Tracfone. It dies, bought new Motorola Moto G8 Plus. Still with Tracfone, Before I called Tracfone up to setup new sim card, I took the old sim card out of the old phone and put it into the new new hone, When I turned the phone on it said Hello Moto, and now after talking and working with Tracfone (On the phone almost 2 Hrs ) I turned on the phone and it does not say anything. Also, How do you keep the desktop light on longer, after I turn on the phone, the screen goes dark after about 15 seconds???? Thanks a lot