Welcome to the SFML forum
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sfml-main.lib is needed if you create a "Win32 application" project ; it allows you to have a standard main() instead of the non-portable WinMain().
sfml-window.lib is needed because you are using the window package
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The rule is simple : if you include <SFML/xxx.hpp> then you need sfml-xxx.lib (and the libs it depends on -- for example sfml-window depends on sfml-system).