https://docs.microsoft.com/en-us/uwp/api/windows.data.json.jsonarray.setat?view=winrt-19041
JsonArray.SetAt(UInt32, IJsonValue) Method (Windows.Data.Json) - Windows apps | Microsoft Learn
Sets the value at the specified index using the provided JsonValue.
method
https://docs.microsoft.com/en-us/uwp/api/windows.data.json.jsonobject.insert?view=winrt-19041
JsonObject.Insert(String, IJsonValue) Method (Windows.Data.Json) - Windows apps | Microsoft Learn
Adds a new entry to the JsonObject.
jsonobjectinsertstringmethod
https://docs.microsoft.com/en-us/uwp/api/windows.data.json.ijsonvalue.getnumber?view=winrt-19041
IJsonValue.GetNumber Method (Windows.Data.Json) - Windows apps | Microsoft Learn
Returns the number (a Double) if the ValueType of the encapsulated value is Number. If it is not, an exception is thrown.
getnumbermethodwindowsdatajson