Documents control the structure of the site, you can nest documents inside each other to create folders and change the order of documents within a folder.
To change the order of a document, select the document to move and click the up or down arrows to move the document up or down in the sequence.
If you are using the [[navigator]] snippet to draw your navigation menus then the order the documents are shown in a folder will be reflected in the navigation.
To move a document to a new location within the document tree select the document, click the move icon and then click the document that will become the parent of the selected document. When a document moves all the child documents are moved with it.