Harold, our Zinger with bunks came the same way, I purchased an aluminum ladder that has hooks on the end that leans up against the top bunk for my kids to use to get in and out, you can get them from many places on the internet, it works really good. It was longer than I needed so I cut it to length so that it sat at an angle and then just reinstalled the rubber feet. When not in use, we just put it on one of the beds or up against a cabinet opposite the bunks.
2011 ZT26BL Zinger
2005 Ford F250 King Ranch
Supercrew, 5.4L, 3.73 rearend
Me and the 'Girls'
Jim, Kristina, Brianna, Kailee, Emma, Nalee the dog and Scout the cat
(even the dog and cat are girls)