Hello there! I am Charity, I'm an Independent Advisor. I'm glad to help you today!
May I ask what is the make and model of your speakers? It should work plug and play.
If your speakers don't automatically become the default device, click on Device properties below the dropdown.
In the new window, click on Additional device properties.
In the "Sound" window that appears, go to the Playback tab.
Right-click on your speakers and select Set as Default Device.
Please let me know if you have any more questions, I'll do my best to respond as soon as possible.
Kind Regards,
Charity
Please note that things might need more than one reply to completely resolve your issue, as it will completely depend on the complexity of the question and the amount of detail that you have provided me.