HI, is anybody here?

Hello, everybody. I am new here. Maybe my English is poor now and I am struggling. That's why I am here! The first thing, I just want to say 'Hello' to all of you.

Hi, is anybody is there?

Hello, everybody. I am new there here. maybe My English is poor now, but I am struggling, so I am here! The For my first time, I just want to say 'Hello' to all of you.

Notes:

In this context "is anybody there" and "is anybody here" both work.

I think it sounds better to say "Hello everyone."

In "English is poor now", the word now can be omitted.