it means you quit the thing on the screen
For consoles: the options is at the main menu when you start the game For PC: the options is anytime during gameplay, just go to the little circle with the "..." in the bottom left corner of the screen, and go to Options.
to enlarge your screen press the little square at the top righ hand corner.
There's a little box in the bottom right corner you can click, but it won't fill your whole screen.
If you mean the screen size, then it is measured by the diagonal of the screen from corner to corner.
Click on the little bag icon in the top right corner of the game screen and click it and there are your items.
If you mean a TV's actual size, you measure the screen diagonally
It is 3.5 inches from one corner of the screen to the opposite corner of the screen.
You will find a little icon in the corner of the playing screen that says "map". Click on it and you will access the map.
Click on the "LD23" at the bottom left corner of the main screen.
You click the little gift box in the right corner of your screen and then choose the gift you want.
Missions appear as bright yellow dots on your map, that you can see in the corner of the screen during the game :)