Only one copy exists after the completed process. Copy means leaving the original in it's location and placing a copy in another location. The end result is 2 copies. Paste means placing an item in a new location. Now the trick is to learn to use it effectively to your advantage.
Lets use the Internet as an example.
Suppose you are doing research on Tarantulas. When you find data that you want in your report, just use this method to add it to your article. Lets use the Internet as an example. Suppose you are doing research on Tarantulas. You search the web for articles on Tarantulas.