Hello need some help with roku remote?

Hi, I got a roku express 4k+ the other day for a small Westinghouse TV I got for free. It's great but the only thing is that I can't get the roku remote connected properly for power and sound. I got a universal remote with the TV but haven't tried it since I have to get batteries.

On the roku remote, the mute button acts as the power button, the volume buttons and real power button don't do anything. When I try the Westinghouse TV codes, the screen blacks out as soon as I click yes to code 4.

Is there anyway to fix this? I can live with it if not, but I would like volume control without having to use a second remote.

Thank you!