Can't figure how to debounce this

This is how I wired it.

This is wrong.

VCC on the chip should be wired directly to 5V not through a 10K resistor.

The inputs on the buttons A to H should all have a pull up resistor on them, that is from the input pin to +5V, make them about 4K7 although this is not critical and can be anywhere between 1K and 10K