Tennekoe Bank help

Call me stupid but when I put in my new T-bank I get the 3 options which
seem to be write from Bank to Console, Console to Bank, and something
which looks like swapping both ways...

Does anyone know what it is? Can I leave the Bank in while I play games
and save games directly to it? Do I have to change a battery in it once
X-number of years? Any other details?