Attempting to make a material test sheet

I am trying to make a material test board. I have followed youtube videos but cannot get the program to highlight the 10 rows of X or Y boxes to make them the same setting. I use the arrow to highlight the box but when I try to draw a box around the 10 rows of boxes, it does not work. I’ve watched several videos, but cannot get by this step! Very frustrated.

This is worth review: Zooming, Panning, Selection - LightBurn Software Documentation

I am not fully understanding your process based on the wording used. Can you click-select a single box shape? If yes, holding the shift while clicking another shape should add the new shape to the selection. If I am totally missing it, please provide a step-by-step description of what you are trying, and we can assist further.