This is the shelf from German amazon. I didn’t use one of the ladders, which are sold separately but used the coloured bendy bridges from ranch house cages which screw to the bars. They are really good as they’re stable and stay where you put them - ie don’t sink into the substrate.
https://www.amazon.de/gp/aw/d/B008OQ...Q6PCDDEQ&psc=1