osl1900

hi please excuse me for not being so good at this stuff ,as i am 72 years old , i have just sold a lot of my old guitar amps and stuff and bought a line 6 xt pro with the fbv express foot controller , i would like to save some of the patches/sounds to the A B C D switches ,i have downloaded the user guide but cant figure it out ,can any of you out there explain nice and easy thanks