2 problems

Because of sloped room you cant get upstairs due to ladder placement. This should have been tested honestly before uploading.

Also how can I get this to actually place so its usable ?
I end up with it too deep in water or with beach filling up the lower area. Is there an easy way to paste this so to speak so that it lines things up such as heigh or do I need the perfectly flat area and know exactly where it was made to be able to use this - it seems almost impossible to place.

I am new so perhaps Im missing something from the plugin in how to use but, any help appreciated to get this to work on a map im using. TY