seen the tutorial using dbx.Files.DownloadAsync(folder + "/" + file) but is there a way to specify saved file location? using c#
The DownloadAsync method offers a way to download files from Dropbox, but it does not save the file to the local filesystem for you. It returns an IDownloadResponse which has a few options to accessing the file data. Specifically, you can get the data as a byte array, stream, or string. Please refer to the documentation for more information on those.
There are a few examples of using these at the following links:
Exactly what you do with the data is up to you. E.g., you can save it to a local file if you wish, using the .NET File API, for instance.