If your equipment only connects via RCA and you need to connect it to HDMI equipment, you'll need an RCA-HDMI converter.
In our case, we're connecting an old DVD player to a TV with an HDMI input.
Converter https://bacomba.ru/av/converter/rca-h...
RCA cables https://bacomba.ru/av/video-cable/3rca/
HDMI cable https://bacomba.ru/av/video-cable/hdmi/