BETH/ETH exchange

Hi, I am a bit confused and I am hoping you guys can clear things out a bit for me.

I am trying to exchange some ETH to BETH and I am required to put a value in these fields. If I put any value there, after I tap “buy BETH” I get this warning.

My questions are - what does the value in those 2 fields represent? - why do I get that warning and what does it mean? - on a little side note, if I exchange ETH to BETH in this way will I get all the staking benefits as I would get if I’d do it directly through Binance staking? Would I need to do anything else?

Thank you, I’ll appreciate all the imput I can get.