All possible constructions can be accessed through this menu. You do not need to know which objects are needed to construct the new object.
The checkable menu-item ’multiple constructions’ specifies whether the next construction should start directly after one construction is finished. You can use this option very effectively like this: Keep multiple constructions checked. Construct single objects by first selecting, then constructing. Construct multiple objects with ’New object - ...’ and stop the construction with ’ESC’ when you’re finished.
The status-bar at the bottom right and (as it seems that nobody ever looks at the status-bar) big letters in the graphics-window show you which object must be selected next. You can cancel the construction by pressing ESC (this will be necessary if you notice during construciton that you have not yet constructed all necessary objects for the object being constructed; only points can be constructed during this process by double-right clicking into the scene).
Example: You want to construct a line.
If you clicked on the wrong object you can deselect it by clicking on it again.
More details on all of the commands are skipped here as they are self-explaining.
See the chapters to locus-surfaces, locus-lines and transformations.