Hey there,
Try this:
1. Open "Finder" and navigate to the file(s) you wish compress.
2. Highlight the file(s) you wish to compress.
3. Control-click or right-click on the selected file(s).
4. Select "Compress filename."
The compressed file should now appear in the same folder and will have the same name as the original, but with a .zip suffix.
B-rock