This deck took heavy inspiration from https://ygoprodeck.com/deck/nouvelles-burger-336553 so check that out.
Rai-Oh is there as a personal favorite as well as a strong option for decks that don't use their normal summon.
Manju is there because of the lack of necessity to normal summon as well as boosting the consistency.
The Impcantations can summon eachother for effect, but are mostly there to be summoned from the deck by Chalislime who will usually send itself from the hand to activate it's effect.
The Nouvellez are set up in a way where their combo can normally be done at least twice, but they can also be put back into the Deck from the GY via Nouvelles Restaurant "At Table", Foie Glasya De Nouvelles, and Dyna Mondo, or into your hand from the GY via Penciplume, Pre-Prep, and Dyna Mondo. There is also plenty of searching and recursion for the Recipe cards that go along with this archetype. The reason I have Fish Recipe at 3 when Meat Recipe is at 1 is because the effect of Meat to flip all defense monsters to attack, while necessary for the archetype, is a more niche effect than adding another ritual spell to hand.
Harpie's is mainly there for the same reason it would be in any other deck, in case your opponents back row is getting scary.
Pre-Prep is at 1 because I forgot to add it, but personally liked the layout a lot and didn't want to change too much in order to accomodate, but you may find that running more than 1 copy boosts your consistency.
I couldn't really think of anything else to add into the Extra Deck, you could add some staples if you want (such as Knightmare Phoenix), or throw random cards in there and add Pot of Extrav to the Main Deck, up to you.
The only things worth note in the Side Deck are Preparation of Rites and Metaverse which should both be pretty easy to understand. Not my first picks, but could end up being useful.
The main goal of this deck is to get your ritual monsters out and rank up through them while tributing everything your opponent has ever loved. You could also just skip straight to the boss monster (Baelgrill De Nouvelles) if you want and there aren't many consequences aside from missing out on a couple effects, but that's what makes the strategy behind this deck so interesting.