Multi-row toolbar? How to make?

I have noticed in many Sketchup videos that the basic toolset and dozens of other more specialized tools, from auxiliary programs, extensions, etc., are organized in a series of rows BELOW the top row, forming a block of icons the width of the display. So far, when I add tools the single row simply gets longer, beyond the width of the screen, requiring scrolling to find the hidden tool icons.

Several rows of icons get a lot of tools out of the way of the image-making. I would like to group these tools together in a multi-row array.

How can this be done? I’m using SU Pro 2018 on a Mac (High Sierra)

Thanks in advance !!!

it can’t.

or perhaps…

As Jack says, it can’t. The videos you’ve seen showing multiple rows of toolbars have been done on Windows. On Mac you get one row across the top. You can add floating toolbars if you want in rows below but the will be over the model space.