c # – Visual Studio opens existing code by clicking on NEW project?

I'm very confused, I started learning C # and I'm using visual studio.
I created my basic program "hello world", save the project. In case you are not in the operating system, you can not do anything.
Of course, I can delete this code and write the new one, but the project comes without all the "USING" (the project comes only with usyng.system).
If someone can help me, I would appreciate it.
When I click on file> New project, this is what appears, instead of appearing a NEW project! "/></p>
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