PSR XS700 USB to Host Interface and usage description

[timeless]

Hi,
I have installed YAMAHA drivers for the USB to Host computer, but there is hardly any place I could find that it would describe that interface and capabilities using different software.
There must be a fair bit of knowledge about it but it is so scattered that a newbie cannot make much sense out of this.
I installed the LMMS but it does not react to the keyboard at all.
Does anupne knows a good resourves page describing the USB to HOST interface, capabiliy and  reliable software that is free?