How do I set up the Logitech K580 keyboard for the first time?

To set up the K580, follow the numbered steps shown in the manual: first connect the receiver or enable Bluetooth, then press and hold the channel button for 3 seconds to enter pairing mode, and finally turn the keyboard On using the power switch. The setup process is illustrated with steps 1 through 3 in the quick start guide. (Page 1)