Not sure what parts I need

Thank you for your patience during this busy season. I'm afraid I don't know what part you need, either. Are you looking to replace that white latch in your first picture?

If so, we may be able to help, but I need more context. It looks like an incomplete assembly. Is there more to it, or is this all there is? Do you happen to have an identical window in the house that still has the entire assembly intact? If so, I'd like to see it. Can you also describe its function?