HOw to load assets for world comp

I created two levels manually , myself inside UE4 and I"d always wanted to do some WC but I wasn’t quite there.
I am now, and I tried to load my levels the usual way or so I thought would be, through the level window, but while they loaded fine obviously as ‘add existing’, they would not line up right so I could sculpt normally, sure I could sculpt, but the added terrain was much much higher on Z so ssculpting made it look like some weird waterfall ;-0

So I renamed terrains to match naming scheme used for importing tiled worlds, and it worked fine, but all my BSP assets and some converted BSP into a mesh, did not make it in as they normally would through a non WC way.

THrough asset loading from menu,or editing my terrain file, is there anyway to get those assets to come in and be where they were designed to me on the level ?

I checked one file but its messy and I couldn’t make out enough of format to know what todo.

Any ideas ?

ty