Nmerali, search the Reference Manual for your Yamaha model for "Multi Pad Editing" or "Editing Multi Pads." Then follow those instructions exactly, and I name my resulting multi pad with the name of my song. That way, I do not mistakenly copy over the original multi pad by mistake.
The result is I have a custom, newly-created multi-pad that could include a keyboard phrase, guitar strumming, a hand clap, and strings -- all working at the same time. It is well worth it.
Thanks, and happy new year everyone.
Jim Duprey