how to add values into array dynamically

I assume your intention is to grow an array by one or more indices - that's not possible. You would have to allocate a new array that has the desired size and copy the values of the old array into it. See Array.Copy(..)[^]

Maybe you should consider using one of the standard Collection-Classes instead, like List<t>[^] or whatever would suit you. Those would handle growing the underlying storage automatically.