External camera connected via usb to I mac
Can someone offer some help please, just purchased a 2 in 1 Camera Nest Box - Pc & Usb compatible , connected to I Mac 21.5 inch I have OS X Yosemite version 10.10.2 running, I downloaded CamWiz Webcam Recorder as software as directed and I now have the inbuilt web cam and the Cam Wiz Webcam both working , However the view on both is from the Camera on the Mac, how do I change between the in built camera and the external camera so I can see inside the Nest Box?
iMac (21.5-inch Mid 2010), OS X Yosemite (10.10.2)