Help with alpine DVD s680 remote

Hello
I am new to this site and new to owning a range rover, we have just bought a 2003 HSE and I love it
I have one major problem and its so stupid and I am sure really simple to answer I hope ......
How do I select disc up or disc down on the remote? I have tried everything though maybe not as I can't get it to work.
please please please help as its driving me mad

I hope I have posted in the right place apologies if not

Thanks in advanced
Tori

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