You can annotate any node by clicking on the "Add Comment..." option in the lower sidebar. This will bring up an annotation form where the field for the node to be annotated is already filled in with the filename of the node you started from. You are invited to fill in the other fields of the form. When you have finished, you should click the "submit" button. The text of the annotation is then sent to the server, which passes it on to a specialised application which creates a new document formatted like the other PCP nodes, containing the text of your annotation. The application also adds links to your annotation in the existing document that was annotated, and in the list of all user annotations. Thus, your annotation can be immediately consulted by other users.
After creating the new document the application sends back an acknowledgment, containing a link to the newly created document.
Since there is as yet no mechanism for editing or correcting annotations, it is best to be very careful when filling in the different form fields, and to reread everything before you submit. If nevertheless a mistake should happen, you can resubmit the corrected version with the word "(corrected)" in the title. The original version with the mistake will then be deleted manually by the Webmaster.