What do Cam Setting Mean

The many settings on your DSLR can be very confusing. I will try to make some sense of them for you.
The green rectangle or green “AUTO” is the automatic mode. The camera decides all the settings for you to get a good exposure. Although this setting takes away some creative control, it allows you to shoot from the hip and not worry about losing a shot. Some people like to set their camera to auto when they shut it off so they can grab a quick shot if something comes up later.
The Tv is for shutter priority. You set the shutter speed and ISO and the camera sets the correct aperture. However, with auto ISO the camera will set that, too.
Av is for Aperture priority. Set the aperture you want to get the depth of field and sharpness you desire and the camera will set the shutter speed.
M is for manual control. You get to set the shutter and aperture. You also have control over the ISO. This can be handy when shooting with an external flash.
Portrait mode will set an aperture to blur the background and set the image mode for pleasant skin tones.
Landscape mode will ensure that everything is in focus. It will also enhance the colors of landscapes.
Use the Sports mode when shooting a moving subject. The camera will use a fast shutter speed to freeze the action.

Read your manual for more detailed descriptions about your camera’s functions. There may be slight differences of functions between cameras.