You can align objects using handle snapping:
Select the first object with the Transform tool and press
to finish the selection.
Press T to switch to the translate manipulator.
To temporarily detach the manipulator from the object, select the handle and press '.
Press
on the handle and choose Align Handle > Start Orientation
Picking. Click two adjacent edges of a face on the object to
move the manipulator to their intersection.
Press ' again to reattach the manipulator to the geometry, so moving the manipulator will move the geometry along with it.
Press
on the handle and choose Align Handle > Start Orientation
Picking. This time, click two adjacent edges of a face on
the other object to move the manipulator to their
intersection.
When you snap the first object’s manipulator to the edges on the other object, it moves and orients the first object.