Paltalk uses your standard PC volume controls.  'What you hear' is played through your Windows default 'playback' device.  First you need to be sure that you have selected your playback device within the Paltalk app itself.  This is usually something similar to 'speakers / headphones (Realtek HD Audio)'

Start up Paltalk and open the settings window by clicking on the little 'sliders' icon above the pal list area (where your online pals are listed)

Click on 'video and audio' on the left side of the settings window.

Use the 'speaker' drop down menu to select your playback device.  This is usually already set to match the 'default' playback device you have set in Windows.

Now try joining some rooms.  You should be able to hear people speaking or playing music.

If not, check your Windows volume mixer.  Left click on the speaker icon at the lower right of your screen.

Now use the volume slider to increase the volume.  Try sliding it the whole way to the right.  You should hear sound or music in the room now. Try hopping around to different rooms to verify that you can hear sound.

If you still have no sound, right click on the speaker icon, and select 'open volume mixer'.

Use the 'Paltalk settings' slider to adjust the volume for Paltalk.

If you still don't have sound, double  and triple check your connections.  Make sure everything is plugged in, turned on, and any volume controls are turned up.