SQL Developer状态：失败 - I / O测试失败：网络适配器无法建立连接

I am a newbie don't know how to use SQL developer. whether I need Oracle database for installing in windows 10 what are these hr and sys users and how to know their passwords. please help me I know this question is asked many times but really, believe me, I have searched a lot but can't find a working solution for it.I am a newbie don't know how to use SQL develop