W A S D - fly forward/strafe
Space / Ctrl - fly up / down
Shift - fly faster
Hold Right-click + move - look
Left-click object - select
Drag empty space - box-select
Shift/Ctrl+click - add to selection
Drag object - move it (whole selection)
Drag arrows / rings - move / rotate
T / R / E - Move / Rotate / Scale tool
Ctrl+A - select all
Ctrl+C, Ctrl+V - duplicate
Ctrl+S - save build
Del - delete selected
B - Toolbox, Y - Scripts
Alt+click - pick one part of a model
Q - switch 3D / 2D camera
2D: WASD / arrows or right-drag - pan, wheel - zoom