yeh, try telling me to use that method after you've had it a couple of months and one of the buttons starts randomly entering double hits etc...hahaha it gets very frustrating!

not sure of the exact uses of those buttons, but yeh you use them in track write mode. mate you need to get the manual, you can find it for download pretty easily

one tip - write a simple measure, program four measures into the track mode. you can then pitch each measure up individually by using aarghgh forget the name of the button but it's on the bottom left

works in pattern mode too but only when you hold it down

anyway dude have fun - get it through some triplet delay, most defo distortion and maybe reverb. crank the gain on an analog desk too...and accents and slides are key to getting the typical 303 sound i reckon