I need some help! I have the white plastic rod twisted ok, the boot back on, and a small hose clamp ready to lock the knob on. When I try to put the S-tronic knob on the lever, it goes down until it makes a click and latches in place - all good. This seems to be as far down as it goes. The knob in this position rotates freely left and right. Is this correct? Do I just line the knob up with the button straight forward and press it in? I am nervous about touching the button unless I am positive all is assembled okay. Comments from those who have done it, please.