by Chris Tyler:
Fundamentals: Guides (Constraints)
This fundamentals video helps to explain what guides (constraints) are and how they help to precisely control movement, rotation and scale in 3D. Note: Design 3D CX interface is shown but the operations are the same for SE.
Shift + X: (held or ‘tapped on’): Activate X guide for constrained movement through X axis (video 1, 1:26)
Shift + Y: (held or ‘tapped on’): Activate Z guide for constrained movement through Y axis
Shift + Z: (held or ‘tapped on’): Activate Z guide for constrained movement through Z axis (video 1, 0:48)
Shift + ; (semi-colon): Guide Tool
This first video is a simple tutorial for new users.
If you want extended basic information about guides and constraints, watch the following video.