There are lots of resources and information from the Confluence User Manuals:
This is a quick start guide taking you through a few steps as the Child pages.
The whole Tutorial is as follows covering the most common activities you are likely to need:
Tutorial 2: Creating/Editing a Page
Tutorial 3: Adding Attachments
Tutorial 4: Comments and Discussions
Tutorial 5 Alerts and Notifications
Tutorial 6 History and Version Control
Tutorial 7: Confidential Information
Tutorial 8: Export to Word and PDF
Tutorial 9: Further information