Sounds like it doesn't move far enough. If you can turn the bike upside down and shift the derailer it should line up directly under gear. If it doesn't then you either have to take slack out of cable till they line up. the cable shoud have no slack when its in the lowest gear. If there is undo the nut that holds the cable on the front derailer and pull tighter with a pair of pliers till all slack is gone. Now try shifting thru gears again . Hopefully this fixed it. There are two adjustment screws on front derailer that will fine tune where the derailer stops for the lowest gear and one for the highest. IF this still doesn't work you will have to go to shop for final adjustment. It shouldn't be that hard, pretty simple to do if your mechanically inclined. Good Luck