I am a tiny bit confused, i choose my background as an simic scientist and it gives spells to my spell list(s), how does that work with my druid(with prepared spells)?

The Simic Spells are added to your class's Spell List. When you prepare a spell, you may select any spells from your Spell List, including those Simic Spells.

Yeah the background spells do not automatically become spells you can cast, they just go on your class list so they can be learned or prepared.