Download the files
Make sure there was a /sites/all/modules/ or /sites/all/themes/ folder on their site
Upload the files manually to the /sites/ folder. Few beginners remembered that folder name – they just uploaded to the /modules/ and /themes/ folder which would be more logical.
Go to Site building > modules and enable them
If you’d like to, you can still install modules the old way, but Drupal 7 also offers a much simpler process: