When you start a new project, you should get a namespace with a quick start page in it. Use the quick start page to create a new file. This will only create a basic template; not all of the fields in the TEI header will be filled out. These additional fields can be filled out or deleted at your leisure.
Existing verses and paragraphs can be edited inline. Simply click on the Edit button at the bottom-right of the section. To add a new verse or paragraph, you will need to click the Edit this page button on the toolbar. Then, start a new <p> or <lg> tag, following the format of the template. Each new <p> or <lg> tag must have an xml:id attribute in order for the collation to work; choose a unique xml:id for each <p> or <lg>. For example, use “v1.1” for the first verse, “v1.2” for the second verse, etc. Each xml:id must begin with a letter.
For a description of how to mark up the text, in terms of line breaks, additions, deletions, and more, see the TEI Tagging page.