Sharepoint - How To Edit a Page

If you have permissions to edit a page in Sharepoint, when you visit a page, you should see an Edit link in the right hand corner of the page:

Click this link and the page will reload in editing mode. It is a WYSIWYG editor like Word. Make your edits.
For example, to edit this list of birthdays, click into the text box and make changes. Copy and pasting can be useful to maintain styling.

When you are finished making edits, click the gold Republish button in the upper right corner. This will apply your changes and reload the page.