Ive been looking at the datasheet for the 74HC4051. From what i can see there are 8 pins and each one can be set to an input or an output. I do have a few questions about them though. Sorry if the datasheet answers these (if it does then i didnt understand it)

I assume i pick a pin for example pin1 (A4) and use it as an output. Then i turn each input on seperately and it will come out of the output pin.

How do i set which pins are inputs/outputs and how do i set which input is active? Im guessing i have to send the data through "COM out/in" (pin 3). Is that serial?

Are the address pins just so you can control multiple chips using a single data line?

Just thinking about the in/out pins. Are they actually an input or an output or do they just turn on/off and any pins that are on will all connect together?