How to get the screen size of what the camera sees

Basically, I am trying to create a game that requires the screen as player sees it to be divided into a grid of squares. I want to know the length and width of the visible area so that I can partition it appropriately. I also want to size the squares appropriately based on the same parameters. So far, I’ve played with Screen.width/height to no avail. I am not even sure what those numbers mean. When I use them, everything is way off from what I expected. Can anyone fill in the blanks?

Screen.widthe/height is what you seek, they return screen width/height starting from left up corner (Like this, if you want to divide the screen you just operate on that value, for instance screen.width/2,screen.height/2 returns the center of the screen. If you want to grid 10 items vertically, you just calculate step by step = screen.height/10 and than
just do simple loop

float step = Screen.height/10;

for (int i=0;i<10;i++)
{
y = i*step; //use it than to move /instantiate your object etc

}