Hi Towjam,
Thank you for your message and a warm welcome to the Cubasis family!
Below please find two tutorial links, where our friend Dom Sigalas explains the MIDI and audio setups using Yamaha’s MODX alongside Cubasis:
Easy-peasy MIDI recording -MODX/MONTAGE with CUBASIS
How I SEQUENCE and RECORD my MODX as AUDIO- Yamaha MODX/MONTAGE with Cubasis
Please let me know if these tutorials are helpful for you, to setup the Yamaha MX88 accordingly.
Thanks,
Lars