Unable to connect a camera MacOS Sierra

Hi there - I'm hoping to connect a camera to my personal laptop (MacOS Sierra, had it for a few years but still runs properly, has never had a camera connected before). I added my user as an admin in Terminal, and I think I added myself to the sudoers list, but killall VDCAssistant doesn't work - terminal just says 'No matching processes were found' when I type it in - and that's pretty much all the advice I've found online.
If anyone has an idea on how I can navigate this, please let me know! But no complicated coding, please...

 

What kind and make/model of camera do you have? How is it connected to your Mac? USB, Bluetooth, wireless?