How do I hide the wires of TV that sits on the mantle?

Cord covers. Can you share a photo?

Wire mold raceway attaches to the wall. Wires go in the raceway. Can be painted.

https://www.homedepot.com/b/Electrical-Home-Electronics-Cable-Management-Cord-Covers-Raceway-Accessories/Legrand-Wiremold/N-5yc1vZc65cZgn8

https://www.youtube.com/watch?v=9JEy4vE9HKM

This may sound dumb, but have you considered a pool noodle but in half? You can paint them to match your decor. Another thought would be paper towel tubes. Again you can slice them lengthwise, tighten it around the cord and paint it to camouflage or match.

Find the wall studs first. Cut a hole in the sheetrock behind the TV and another down low behind your components. Use a fish tape (or heavy wire) to run between the holes. Fasten the wires to the fish tape and pull them from one hole to the next. Add a cover plate at each location and connect wires to TV and components. Pull a spare sting between the 2 locations in case you need to pull more wires later. I found cover plates at Home Depot that have plastic brush at the rectangular holes in the middle of the plate. Multiple wires can fit through these openings. I have seen some You Tube videos that show the process.

I agree with Naomie and William. The cord covers are the easiest way to go and look good. You can get curves and corners if needed. Most are installed with screws or self adhesive tape. There are even different widths depending on how many wires you want to hide.

Thanks everyone I got the covers on amazon

Find a pretty box or basket cut a hole in the back put the cable TV box and DVD player in the box and run the wires out the hole - find some masking tape and tape the wires away then paint the tape the same color as your wall or fireplace - masking tape holds latex paint.