In the first case you have not intantiated the object. As a result, you only have access to the classes static methods.
Ine the second case, you are actually allocating a location for an instance in memory. You are actually creating an object of that class. This is what you would do in OOPS. Create objects and then set properties for each of these objets.
There is tons of information about this on the internet.
Something like
this[
^] should be good reading for you.