We just got a Bosch d/w too - how spectacularly crap the instructions are! As for the installation leaflet - it might as well have been in Chinese - I hate how in order for it to be used in any country, they make it equally incomprehensible to all (and yes, that means you too Ikea).
The stuff you need depends where you live: we don't need salt here because we have very soft water. But most tablets these days have salt and rinse aid in them already. I have always found that the eco d/w tabs are actually better than the Finish all-singing stuff you pay through the nose for.
It depends if you live in a hard water area, I find if we don't add salt our dishwasher starts to smell and doesn't work as well... Salt really doesn't cost much, get supermarket own brand dishwasher salt.
Rinse aid is purely down to choice... try a few washes and see how you feel about it.
Oh, and I think the rose thing is a special attachment for doing baking trays. We didn't get one with ours, but I seem to remember reading something aout it in the instructions. Perhaps the installation instructions.
I use both salt and rince aid, only cheap stuff. I am in a hard water area so need salt. I find without rince aid, things come out wet whereas with rince aid plastic cups etc are dry. Makes it easier to empty!