Welcome to the forum! You should include your VIN number and contact info with your post. Other forum members will reply but I don't think Heartland will without your VIN and contact info. There should be backing there, I think it starts on the right side (as you stand behind the camper) and is spaced over 16" but let Heartland confirm that. We couldn't get a ladder from Heartland, our dealer ordered one and installed as part of our deal. You can also call customer service (877) 262-8032 or email
service@heartlandrvs.com (not a link but is their address).
Good luck with the ladder and happy camping!
Cliff and Mindy