well i cant figure out how to edit switches.. er ill give u an example this is probly really easy but oh well

ok the king gives me a key and with this key i want to open a door... i wanna use the key on the door and the key dissapear and be able to enter the door forever after that and i want the king to say something diffrent after i slay the evilness in the cave.... or what ever is behind the door..oh ya and i dont wanna get the key from him after he gives me the key i want him to say something diffrent, i tried if im holding the key he will say something diffrent but when the key dissapears into the door if you go back to him he would give u another key right?... another one how do i make someone say something diffrent for if i chose yes or no and then i want them to walk out of the screen and then be next to the king on a diffrent map...and not be back where they were when i go to a diffrent map then back.