C# wait for a function that returns void to finish a System.NET.WebClient.DownloadFileAsync() while still keeping an active WinForms UI

Question

The download function downloads async so that the UI doesn't freeze, but I need it to download one file at a time, so I have a second function called downloadall() that needs to call the download function, then wait fo the file to be downoaded and installed (this is a bool variable), then call the download function again

public void Download()
{
  using (WebClient wc = new WebClient())
  {
    wc.Credentials = new NetworkCredential(User, Password);
    wc.DownloadProgressChanged += wc_DownloadProgressChanged;
    wc.DownloadFileAsync
    (
      new System.Uri(DownloadURL),
      path + Name + ".zip"
    );
  }
}

        private void DownloadAllBtn_Click(object sender, EventArgs e)
        {
            foreach (Pakage p in Program.Pakages)
            {
                if (!p.IsInstalled)
                {
                    Download(p);
                }
                while (!p.IsInstalled)
                {
                    ///wait without freezing UI
                }
            }
        }