How to Place a Construction Element in ARCHICAD

Use the Favorites Palette: double-click on stored Favorite settings for the relevant tool, then click to place an element with those settings.
Use the Magic Wand to create new elements that automatically match the shape of an existing element (e.g. create a Roof that fits exactly over your exterior Walls).
RoofMaker and TrussMaker from the Design > Roof Extras or Design > Design Extras menu.
A new element placed in a 2D model window is at the level of its Home Story (plus or minus any optionally defined offset).