• Click "New Baseline" to create a Baseline
  • You will need Create Baselines permission to create baselines. If you can't see the New button, contact your Jira Administrator to get permission.
• Enter a name for the baseline
• Select a date for the Baseline
  • For each document (page or attachment) in the space, the latest version that has a date earlier than the given date will be included in the baseline.
  • By default, the dialog shows the current date and time

• Select the scope of the baselines
  • Include All Pages
    • This option includes all pages (and attachments on those pages) in the space
  • Select Individual Pages
    • This option allows the user to select individual pages to be included in the baseline.
      • Attachments on selected pages will be included in the baseline.
    • Mark the checkbox next to each page that you want to include in the baseline.
    • The menu icon next to the checkbox of each page opens a context menu which allows the user to select or deselect a page with all its subpages.

• Click Advanced and enter a baseline keyword, if any. (Further information about the use of Baseline Keyword is down in the document)
• Click  "Create" to create the baseline.
• Your new baselines will be displayed as part of the baseline list on the left

Baseline Keyword 

You can set a keyword to pick individual page versions from each page's history. When you enter a keyword, the plugin searches for the keyword in revision comment of each page version and includes the newest version (that is earlier than the selected date) that matches.

This capability can be used to filter out draft versions of a page. Since each "save" creates a new version, you can enter a specific word in document revision notes for major versions of pages and using the "Baseline Keyword" feature, you can make the plugin pick those versions from the page history.

If you do not use keywords in history notes (or if your are not sure how to use this feature) just leave the keyword empty.