Shifter 1987 camero

I just got this car, and it need some fixing, and i can't seen to remove the Shifter nob, and i need to remove the nob to get into the underneath, this is an automatic BTW...

there is a small protruding slot that is holding it on i think... and i have tried to move the slot, but i don't want to break anything


any help would be useful


thx