Look backing at some of your previous postings, you seem to be interested in mixing the various keyboard voices you are using in your OTS settings.
I don't know of any tutorials that have been posted and shared. I have been able to pick up tips from my attempts to create custom song styles. By trying to put together a custom song style from just hearing an actual successful commercial professional arrangement, you could learn what works.
If you trying to mix instrument sounds by layering them to produce a midi to play along with, I still think you would learn best from first trying to copy a professional song sound mix.
Regards,
Drake