I am trying to get back into music production and recently got the XF8.
I also have the MG16XU (mixing console).
Please any help on the best way to connect using the sequencer in the Cubase AI7 which I also recently downloaded courtesy of the mixing console.
I will be using a MacBook Pro.
Thank you.

Welcome to Yamaha Synth! And congratulations on getting back into music production.

The best way to proceed will depend entirely on your specific goals. Your goals will have a big influence on developing your workflow. Music production being such a broad subject, it would be impossible to tell you exactly how to proceed. But here's a starting point, based on the gear you've mentioned:

The Yamaha MG16XU is a mixing desk which can act as a 2-in/2-out interface for your computer via a USB connection. The MG16XU will connect to one of the USB ports on your MacBookPro. The Motif XF will connect to one of the stereo channels MG16XU via two 1/4" instrument cables. In general, all devices you wish to record to Cubase will need to connect to the MG16XU. It then can send a stereo signal to Cubase for recording.

The USB cable also 'returns' a stereo audio signal from the computer to the MG16XU for monitoring (listening) purposes.

You will need to connect the Motif XF via USB to a second USB port on your MacBookPro to handle MIDI communication between the XF and Cubase. This will allow you to synchronize the clocks (so the tempo selected in Cubase will determine the tempo of all tempo driven functions in the XF: Effects, Sequencer, Arpeggios, LFOs, etc.) and you can utilize the "Motif XF Editor VST" to manage your Motif XF sounds (Mixing setups, Voice Libraries), and other functions. The USB connection between the XF and the computer is for MIDI data only. All audio from the Motif XF will travel 'analog' to two channels of your MG16XU.

By synchronizing clocks between Cubase and the XF you can confidently ensure that overdubbing tracks to Cubase as audio can be accomplished with precise timing alignment. Cubase becomes the Master clock and you would set the XF to MIDI SYNC = "auto". This will automatically tell the XF to get tempo cues from the DAW (Cubase). You will also set the SEQUENCER CONTROL = IN; this allows the XF to take transport messages, Stop/Start/Continue, Locate, etc. from the DAW (Cubase). This settings are found in [UTILITY] > [F5] CONTROL > [SF2] MIDI

With a 16 channel mixing console you can record several external instruments to Cubase. The Mixer combines all signals and sends a stereo signal into the computer: Live to Stereo. Alternatively, you can "multi-track" where you record-and-overdub to build up your multiple tracks, one at a time. This is what I meant by "your workflow". If you are looking to document an entire "live" ensemble recording, you would connect all sound making devices to the MG16XU and record the entire band to Cubase, simultaneously. Or in the scenario where you are multi-tracing you can build your audio tracks - some with the XF, others live but using the "Les Paul" method of multi-tracking. How you go about music production can vary project to project.

How do you envision going about music production?

See: "Using the MG-XU console as an Audio Interface"

Thank you Bad Mister this has been highly useful.
I actually intend to start using the XF as a master keyboard which like you said will be connected to the MacBook.
I was worried about the signal paths but I think I understand its actually better like u said connecting both the XU and XF to the computer and controlling via Cubase.
This way only other external instruments will go via the XU and I can still blend in sounds & effects from the XF directly and comfortably.