QUOTE(yongtjunkit @ Nov 4 2019, 09:40 AM)
The one from the RF out from the DVB T2 decoder to the TV analog input
Already hooked up hdmi, but unfortunately my aunt press the CH + , CH - button on the TV remote instead of the decoder

According to Wikipedia: Male (left) and female Belling-Lee cable
Belling Lee connector cable is also known as TV aerial cable or PAL cable.
Anyhow, it's not necessarily must buy this specific type of cable.
You can use RG-6 coaxial cable (Astro white cable), and terminate the ends of the cable with whatever connectors you want, including Belling Lee connector, either male or female port.
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If your aunt gets confused by using either TV remote or the Digital TV remote control, then just tell your aunt to use only the digital tv remote, and stop using TV remote completely, including adjust audio volume.
You adjust TV volume higher a bit, then tell your aunt to use digital TV box's remote to adjust the volume, not the TV. Then, you keep the TV remote somewhere else in the drawer or something. Take it out only when you need to change some other settings on TV, or use other smart TV functions.