To experience all the features the sound card offers, it's best to use the 3.5mm outputs instead of SPDIF. If you want to use your amplifier, four(7.1) stereo 3.5mm-to-RCA cables can be used to hook it up.
Those inputs you highlighted are correct if you have the Marantz SR7500.
You can also connect the optical cable for the highest quality sound. Switch between the two audio inputs whenever you like since your video signal won't be able to bypass that amplifier anyway (no HDMI and DisplayPort).
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