If you click and drag the first helper; the current object or the currently selected set of objects would get dragged. You can now place the object anywhere on the currently visible portion of the site.
There is a more precise way to drag an object: When ending the drag; you should drop the mouse right on top of the architect . If that be the case, then the object (or selected objects) would get precisely shifted to the location of the architect.
By precise; I mean that TAD determines where the first helper used to be located; and then displaces the object/s in such a manner that the first helper would potentially be exactly on the architect.
Once an object is dragged in this fashion; you would find that the archiect would not place itself right on the first helper (i.e. the architect would get magically be shifted from its earlier location to that of the first helper) If you do not want such a behaviour; use the software's Properties dialog and change a checkbox
Press F1 inside the application to read context-sensitive help directly in the application itself