How do i use my iMac and the macs wired internet connection to share the internet with my iPod and iPhone

How do i use my iMac and the macs wired internet connection to share the internet with my iPod and iPhone. For 6months I had set up a network that shared the internet through bluetooth to my iPod 5th gen but i messed it up when i tried to add my iPhone 5s and i can't remember how to do it.