How to connect Oppo BDP 95 and Mcintosh MX136

As on page 7 of your manual, use:
• External Eight Channel Input
An external eight channel signal processor can be connected
to these inputs as well as a DVD-Audio Player or Super
Audio Disc Player with a built-in processor.

Thank you very much.
Only 2 rca cable from Oppo to Mcintosh are not enough?

Two are appropriate for stereo. More for multichannel. Since you asked about surround, the latter would be needed.

if your MX -136 does not have multi channel RCA input, then you need to use the MX-136 HDMI input from the Oppo in order to get surround sound.
The Oppo's 2 RCA outs are for the audiophile stereo only section of the Oppo and will not get you multi channel sound.