There’s quite a few things that need fixed. I’ll start with the bracket at the bottom of the ladder. It consists of two parallel faces which are only connected by the holes in them. There should be faces all the way around the perimeter too.
Unfortunately, the screen capture sofware I use, LICEcap, doesn’t record my keystrokes so I’ll try and explain them here. I selected both plates and made them a group. Selected the face furthest from the ladder and cut it to clipboard, clicked out of the group, pasted in place. Edited the group, push-pulled the face until it met the face I pasted outside the group. Then deleted the face outside the group. Edited the group again, softened faces to make the facets on the inside of the holes smoother.
To clean up your model, I’d delete all the tubular faces of the ladder. When you do that, you’ll see some stray edges that need deleted. You’ll also see some of the rungs don’t touch the upright edge of the ladder. One of the rungs has a centre line that isn’t level or perpendicular with the upright stringer of the ladder. Clean all of those things up before you start to use follow-me to create the tubes.
My 3-D Drawing_gm1.skp (211.6 KB)