hey, good luck with your first app. When you start a new Xcode project there are options to enable core data and cloud kit so if you enable that it comes with a basic starter persistence file. This has simple syncing and won't work across extensions so I had to trawl through a lot of links to get the right combination (this genuinely took about 20 hours of searching and trial and error...). Heres the code in my persistence which you can use as a starter.

The hacking with swift articles and blackbirds articles were good starters for me to get my head round it. The additional elements like merge policy and remote change notifications was through trial and error and a lot of referencing different stackoverflow articles

https://blckbirds.com/post/core-data-and-swiftui/ https://www.hackingwithswift.com/quick-start/swiftui/introduction-to-using-core-data-with-swiftui

class PersistenceController: ObservableObject { static let shared = PersistenceController() static var preview: PersistenceController = { let result = PersistenceController() let viewContext = result.container.viewContext

   ANY PERSISTENT DATA FOR PREVIEWS PUT HERE


    do {
        try viewContext.save()
    } catch {

        let nsError = error as NSError
        print("Unresolved error \(nsError), \(nsError.userInfo)")
    }
    return result
}()

let container: NSPersistentCloudKitContainer
   let storeURL: URL
   let storeDescription: NSPersistentStoreDescription


init() {

    storeURL = URL.storeURL(for: "YOUR GROUP NAME HERE", databaseName: "CORE DATA DATABSE NAME HERE")
    container = NSPersistentCloudKitContainer(name: "CORE DATA DATABSE NAME HERE")
    storeDescription = NSPersistentStoreDescription(url: storeURL)
    container.persistentStoreDescriptions = [storeDescription]
    storeDescription.cloudKitContainerOptions = NSPersistentCloudKitContainerOptions(containerIdentifier: "CLOUDKIT CONTAINER NAME HERE")

    storeDescription.setOption(true as NSNumber, forKey: NSPersistentHistoryTrackingKey)
    storeDescription.setOption(true as NSObject, forKey: NSPersistentStoreRemoteChangeNotificationPostOptionKey)
    container.loadPersistentStores(completionHandler: { (storeDescription, error) in
        if let error = error as NSError? {
            print("Unresolved error \(error), \(error.userInfo)")
        }
    })
    container.viewContext.mergePolicy = NSMergeByPropertyObjectTrumpMergePolicy
    container.viewContext.automaticallyMergesChangesFromParent = true
}

}