D-link DMG-6661

How to install OpenWrt in D-Link DMG-6661?

If it isn't listed in https://openwrt.org/toh/start, you can't.

While it might be technically supportable (but I can see barely see any hardware information[0] about it, so I can't even say if it would be supportable in theory), someone with the device on their desk would still have to spend considerable time to work on getting it supported.

[0] it seems to be based on the BCM63268 SOC, which would suggest that WLAN is probably not supportable, with other problems to be expected.