You may also wish to read the instructions for organising your site content.
Click the "Add content" link at the top-left corner:
In most cases, you will want to click "Basic page", although some sites may have extra custom content types defined. First, give the page a title. You can then optionally upload a "Leading image" by clicking the Browse.. button, choosing an image on your hard disk, and then clicking Upload:
An image uploaded in this way will automatically appear at the top of the page, in a layout that matches the standard template as illustrated in the following screen shot from the main University website:
Finally, in the box labelled "Body", insert the text that you would like to appear as the page content. At the bottom of the page, you can click "Preview" to see how the page will appear, and then click the "Save" button when you are finished.