Click a category, pick a piece, then click the plan to drop it — or drag it straight from the palette.
R rotate the ghost while placing · Esc cancel placing
Pipe & Drape and Wall (under Miscellaneous): click each corner to lay a run of any shape — straight, L, U, zigzag. Double-click (or Enter) to finish, Esc to cancel. Pipe & Drape gets base plates automatically at both ends, every corner, and every 10ft along the run; a Wall draws as a solid partition instead.
Select / Move tool: click to select, drag to move, drag the handle to rotate.
Del delete selected · [/] rotate 15° · arrows nudge · Ctrl+D duplicate
Box Select tool: drag a rectangle to select everything inside it at once — then Del or Ctrl+D to delete or duplicate the whole group, drag any one of them to move the group together, or drag the group's own handle to rotate all of them together. Shift-click an item (in either tool) to add or remove it from the selection.
Hold Shift while dragging any rotate handle (single item or group) to snap to 45° angles.

Which 3D scene should the PDF's 3D page show?