How to setting Android Package Name ?

Excuse me, this is my first time publishing games.
I have a problem about setting Android Package Name .

I don't know how to setting it.ヽ(≧Д≦)ノ

Please forgive my ignorance.｡+ﾟ(ﾟ´Д`ﾟ)ﾟ+｡
Can anyone teach me or share tutorial about it for me?