To edit a whole page of your wish first get to it (navigate to it).

Once you are looking at the page you want to edit, click the "Edit Page" button (found
at the top and/or bottom of the page), and make your changes to the code of the page.

If the page you want to modify is quite big and has lots of headlines that divide the content into (logical) parts then you also can edit those parts instead of the whole page.
Click one of the edit links on the right of each headline to get into edit mode for this part, defined by the headline and its level.
While you edit a page, it is locked for other users until you finished your edit session (by saving or cancelling) or until you reached the timeout. The timeout depends on the administrators settings and is by default 15 minutes.
This lock is always set for the complete page, even when you edit only a part of it. So no real time collaboration on one page is possible with GeboGebo.

Before you save your changes you should take a look onto it with the Preview. It will display your page as it will be displayed, after you saved it. The page is kept locked to other users until you finally press the Save button.

If you are a logged-in user, then you have the possibility to declare the page to be locked for anonymous editors. This makes the page uneditable for users who have not created an account.

Check the checkbox keep current revision and avoid history entry if you think your change was too unimportant for others. This also avoids that notification emails to subscribers are send, if you are a logged-in user.
Anonymous users can't avoid email notifications to subscribers. This is a control mechanism against spammers and other malicious edits.

The Log text area takes your up to 255 characters long desciption of the changes you've made. It will appear in the pages history, any notification emails to subscribers and in the RSS-feeds.