Renaming pages
To rename a page, click on the "Page Info" -link of that page. If you have sufficient access rights, you will see a box with a title "Rename page", and the name of the page. Type in a new name, and click on "Rename". This will change the page name.
If you check the "Update referrers" -box, then JSPWiki will change the text of all of the pages which contain a link to the page you are about to rename, so all the links will still be correct.
However, note that "Update referrers" will cause a large number of updates in the recent changes list, so be careful when you use it!
Deleting pages and attachments
To delete a page, click on the "Page Info" -link of that page. Similarly to the Rename functionality, you will see a button which says "Delete this page", if you have sufficient access rights. Clicking it will remove the page.
To delete an attachment click on the picture of the paperclip; that will take you to the attachment info page, then click on "Delete attachment".