Hello Andi,
Important: Never use any type of window cleaner, soap, scouring powder, or any cleanser with solvents such as alcohol, benzene, ammonia, or paint thinner. Never use abrasive pads or paper towels. If you do, you can scratch the screen or strip the anti-glare coating off the screen and cause permanent damage.
It's also important that you never spray anything directly onto your TV screen and wipe as gently as possible. TV screens are fragile and can be damaged when pressed too hard. Before you plug the TV back in, let the screen dry completely.
For general cleaning of both the frame and screen of your TV, use a microfiber cleaning cloth and water. Do not spray water directly onto the TV, but apply a small amount of water on the corner of the microfiber cloth. Never use cleaning fluids, wax, or chemicals.

Turn the TV off and let it cool down for a few minutes before unplugging it. To clean the screen, gently wipe it with a microfiber cleaning cloth. If you don't see results, spray water directly to your microfiber cleaning cloth and wipe. ^Cristian

Hello,
Yes, you can download the Roku app from your TV's built-in App Store. ^Cristian

Hello smw81151,
Yes, the 65TU8000 will be compatible with your soundbar. ^Cristian

Hello Bill,
The major difference between Crystal UHD and QLED are in its display technology. With QLED you get Quantum Dot Technology 100% Color Volume. Over one billion shades of pure accurate color. With detail at any level of luminance, Quantum Dots are durable and scalable to deliver the same amazing picture across various models. ^Cristian