I need help putting together my new kit, it's Xpress brand. First, how do i put the wheels on? If i leave both of those octa,hexa gon thingys on the wheel wont be able to screw on, but if i leave one on, the wheel is too lose... Second, how am i supposed to fit on the ball end cups? Is there supposed to be a special tool? Because I haven't been able to push it on any other way. Please help!