For help on Google sites go to: https://sites.google.com/site/siteshelphowtos/google-sites-instructions
Sharing Google Sheets
To share Google Sheets with others follow these steps:
1. On the far right side of the Google sheet you want to share there is a button that says Share. Click on this button, then click Get Shareable Link.
2. Change to "Anyone with the link can edit".
3. Click Done - once updated the Share button will change from having a padlock on it to showing a person on the button.
If you would like to get notified of any changes to the Sheet click Tools> Notification Rules. Set notification rules as required.