Basically, if you have enough points, you apply for a green card and you get it.

That's it :)

That is not exactly how it works in Australia. You get enough points, then you qualify for the visa, then some office worker arbitrarily decides if he feels like giving it to you.

Yes, but how do you gain points?

You get points if you are skilled in a job the country needs, you have X years in your field, you have a bachelor's degree, you have a master's degree, you fit into certain age brackets, you have an Australian spouse, you have other family in Australia, you have a job offer, etc.

http://www.isa.com.au/points-test

Pretty much, if they want a flood of worker in a certain industry, then they give you points if you have exp in that industry.