If audio is not coming through on your Zoom calls or is coming through the wrong source such as your monitor, you can change the audio source through the Zoom settings.
With Zoom open, click your Initials or profile picture at the top right, and select “Settings”
Select “Audio” on the left side. Then, click the drop-down menu under “Speaker”. Select “Same as system” or “System default” for the audio to come through the laptop speakers. You can also modify the Microphone input below the speaker options to switch between external microphones or a webcam.