being that your car is a 4 cylinder there is only 1 bank, if your car had 2 heads then bank 1 would be the head that cylinder 1 is on, and bank 2 would be the other head. bank 1 sensor 1 would be the oxygen sensor BEFORE the catalytic converter, bank 1 sensor 2 would be the o2 sensor on bank 1 that is AFTER the converter

just keep in mind you can get a code and it may say something like , system too lean bank 1, that doesn't mean it's an o2 sensor, it can be don't get me wrong, but o2 sensors monitor and that lean code can be caused by an intake leak or a maf problem, or a dirty injector, or an exhaust leak or whatever. the reason i'm saying this is cause the kids at the parts stores that scan your codes, sell parts. they're not mechanics. so whenever they see the words BANK 1 they're like "must be a bad o2 sensor, our piece of shit $79 scanner won't tell us if it's the upstream or downstream one but we'll sell em both for $XXX" meanwhile you wasted your money on two parts you have to put on yourself or pay someone to put on and it's not even going to fix your problem.

anyways hope that helped, if you're still stuck post again