The Razer Kraken Pros should come with an adapter to convert its single cable into a double cable. But from my understanding your PC has only one port. Just ditch the extender and plug the 3.5mm cable into the audio jack.
If you have trouble configuring the audio, check below to see if this will help.
I have Realtek HD Audio Manager on my laptop (as you likely do)
When you plug a new audio device (like a combined 3.5mm jack for your headphones) it will (most of the time) prompt you if the new device is:
If you pick speaker it will default to the mic on the laptop and the audio on the headphones.
If you pick Headphones it will use the mic and audio on the headphones
I dont know if you have this same sound manager, but if you do, you can force to prompt box to pup up
⊞>"Realtek HD Audio Manager"
Look for the panel on the right labled "Analog"
There should be a small folder in the top right corner of that panel.
Click it and enable "Enable auto popup dialogue, when device has been plugged in."