How do you know?

To whom it may concern:

You make these claims about God and the Bible,
but you never justify them; ultimately, you say
“it’s faith”, which doesn’t impress me much.

Do you know that YHWH exists, created the universe
and then had something to do with writing a book
that frames Him commanding for genocide,
race-based slavery and public-participation
torture-to-death frenzies?

IF you do claim to know, HOW do you know?