Not that complicated if you try hard, took me about two weeks working one or two hours a day to figure out how to use the UE4 looking at online tutorials and every time I had a problem I just wrote the question on google and it would redirect me either to an explanation in the documentation or a UE4 forum post with the answer.
To get the measurements right I built the model in 3dsmax and placed all the pivots on 0,0,0 (while leaving the building in its place,just move the pivots not the building) sot that when you place it in in ue4 you just have to place them at the origin and all the pieces will align.