Dropbox account and App installed on your iPhone or iPad
Create a PDF of your current logbook
Open Logbook App and go to settings export
Select the PDF type you would like to upload to Facebook
Export it to Dropbox
Select the Dropbox 3rd party App
Change the document name if you like, and select a appropriate folder to save the logbook. Then press "Save".
Wait until your Logbook is uploaded to Facebook
Press the circle with the down-arrow right to your Logbook and select "Send Link"
Only if Facebook is not available, select "More" and enable Facebook as "Activity"
Select the Facebook App as target App for your link.
Write your post for Facebook
Write your individual post to Facebook, and go back to the Logbook App