Teach your kid how to open their lunch box, use the bathroom, and interact with other kids to prepare them for prek

Our three year old will be starting school at a place with 90/10 Spanish immersion program. He’s had nearly zero exposure to Spanish so far. Any advice on how to prep him? School is such a big change, so trying to make him more prepared for the situation. Are there any bilingual streaming shows (for preK age) that could be helpful?

I welcome any other pre-K preparedness tips as well!