To view file info, click the Get info toolbar button, or the Command+i hotkeys.
You will get the profound file info, such as size, creation date, sharing and permission rights, etc.
If you select the folder and click the Get info toolbar button, you will get the size of the folder and of all its contents. Note, that counting and displaying the folder size may take some time, depending on the folder size.
Note: If you click Alt+Command+i, you will invoke the File Info of Finder.