As far as placement goes...

Scenes handle loading additional objects two ways. A> The additional items come in at pre-defined places in the scene, or, B> They load dead center of the scene.

If it is the latter, then all you have to do is use the translate X,Y, and Z controls to place the item wherever in the scene you want it. Hint: If you want it near something else in the scene... note the x,y,z coordinates of THAT item, then click on the new item and move to those coordinates. That gets the new item "in the neighborhood."