USB interface with PIC18f4550 and labview

i'm currently upgrading my lecturer's project which is,
Data Acquisition System for a portable electronic nose..which use the USB module of the PIC18f4550

i have get the code for the usb interface for pic18f4550
but, i dunno how to modify the code/create my own mplab coding for

1) reading the data from 3 x 200 gas sensor arrays which total gas sensor used is 600 (chemoresistive sensors)
2) send the data from the gas sensor through usb cable
3) view the graph waveform of the resistance versus time in labview

i can handle the labview...but i have no idea n have no basic in microcontroller programming...plesae help me... =( or else i can't graduate..