Connect USB speaker

How do i connect a USB speaker to an Arduino UNO board?

With wires. One to the signal and one to the ground.

What do you want to do with it once you have connected it?

After connecting the speakers i want to play some basic sound using the the tone() function.

I don’t even know if it’s possible, but you’d have to write a USB audio driver. Then, you’d have to re-write the tone() function to communicate with the driver. And, you have to deal with the fact that the Arduino is normally a USB device and you need it to operate as a USB host controller. Not really practical…

Or, you can try hacking-into the speaker’s analog circuitry.

…Or, just get some regular analog computer speakers.

Have you really got a speaker whose only connection is a USB socket?