The round connectors did not work at all for me. The vibration of the buns jumping up and down loosened them within a couple of weeks of installation, so I finally gave up and went with all cable ties.
OK, so getting it to stand up.As long as your base is wide enough (mine is 3×2 on the first floor), you can just let the cube walls rest on the floor, and if you zip tie everything tightly, they stand up on their own. You make a floor (say 2×2 for this example) and zip it together. Now, you zip a set of panels at 90 degrees from the floor, zipping the top edge of each panel to the floor, and at the corners, zipping the two perpendicular squares to each other. Once you go all the way around, you’ll end up with a rectangular solid with no top. Turn it upside down, and there it is, the first floor of your condo! The second floor is the same, except this time instead of resting the side panels on the floor, you zip them to the first story. You leave out some of the internal panels to make shelves or to make vertical space. When you are done, you cover the wire on the flat surfaces. I use plywood, you can also use coroplast, carpet, rugs, anything to keep the buns’ feet off of the wires. I learned the hard way to use something sturdy; Curly Sue developed sore hocks from walking on thin mats thrown over the wire floor. Make sure to leave yourself some access points for cleanup, litterboxes, grabbing buns for snuggle time, etc. I did this by leaving a few top panels unzipped, and closing them with clothespins when the buns are supposed to stay home. I guess if your bunnies do not jump you can just leave the top open, but I actually closed mine all the way.
It made no sense to me either when I started making ours, but it is like a big lego set, you just sit on the floor, try various combinations, cut and re tie when you mess up, and eventually you come to understand how to get it to work. Have lots of zip ties on handl, you’ll use them all! it isn’t hard to do, but it is hard to explain If you make it wider than 2×2, you will likely need some wooden dowels or 1x2s to place across the bottom of the flat surfaces so that the flat surfaces do not sag when bunnies stand on them. Again, once your condo is together, this will become obvious. No tools are required other than a saw to make the lumber the right length, it attaches by sliding it through the grids.
Now, ramps. I have none, mostly because they take up floor space. I opted for shelves, and even our tiny two pound wonder Deanna can navigate up and down with no trouble. From the floor to the second level is a one panel jump (14 inches I think), then I have a shelf at about 8 inches to allow them to get to the third story. We put unused ceramic floor tiles (12 inches by 12 inches) as a floor on the shelf to protect their footsies. Our whole condo is basically 3 panels by 2 panels, and it sits inside of a 4 foot by 4 foot XPen.
Good luck with it! Once you get the hang of it, it is actually alot of fun customizing these set ups. Who ever dreamed up the idea of making rabbit housing out of wire shelf units was a genious!
If I remember I’l take a picture of ours so you can see what the heck I am talking about.