The PS4 usually ships, with one controller which you must connect to the console for the first time with the USB cable supplied. Once connected you can use it to control the console wirelessly, until you reset or use it on another console. You can also connect a new second controller with the usb cable, however it can also be connected wirelessly. Here is how;

Let’s say you just purchased 2 controllers for your console, this is what you should do.

Switch on the console.

Connect one of the controllers to the console using your PS4 USB cable or a compatible one.

The controller will glow if USB cable is properly connected.

Press the PS button on the controller, then logon to an account on your console.

Now go to, SETTING-DEVICES- BLUETOOTH DEVICES

You will see the already connected controller and the account it is connected to.

Now, to connect the second controller wirelessly; press the, PS button and the share button simultaneously for  about 5 seconds until the controller blinks.

The console detects the controller and it is shown on your TV screen under Bluetooth devices.

Use the first controller to select and register this second controller.

Immediately, the second controller is available for use with the console.

Subsequently, you can connect more controllers using this method.