Elements can be selected by clicking on the desired element in the central Editing Window.
While holding the Ctrl
key, if you select a different element that is not currently active, the newly selected element will be added to the selection along with the current one. This can be combined with Select Elements by Range below to add or remove elements more flexibly.
If the elements you want to select are gathered in a certain area, you can activate the range selection by clicking and dragging from an empty space with your mouse. Continue dragging until the desired elements are within the selection box.