You can get to the Daily Pledge from the Home page (or from Celebrations & Events).
Then click on "Take the Daily Pledge"
On the next screen scroll down and click on the current month...
When the Pledge pops up, click on Latest Reply.
From that page scroll to the end and click on "Reply to original discussion."
Make your pledge then click on "Add Comment." Also see: About Daily Pledge & How to Participate