COPEPOD data files retrieved directly from the online database are compressed with "ZIP" compression and have a ".zip" extension.
These "zip" files contain a single compressed folder what contains multiple files and folders inside of it.
You should unzip/extract the entire COPEPOD zip file "as-is", so it will appear in your folder/directory correctly (i.e. a folder or folders with multiple files in each folder).
Extracting file-by-file or otherwise may create a mess of randomly distributed files.
For example, if you view the ".zip" file (e.g., with WinZip), it may look like a mess of random files.
The files and folders will correctly re-organize themselves during the unzip process.
We use the shareware "Info-Zip" software, which is available for pretty much any computer on the planet. It is available at: www.info-zip.org/pub/infozip/. This link will take you away from this website.