I found holding each piece with tweezers helped better align.
You can hold it better. Use other hand to help steady.
You can also see better when lining up the pie sections.
My suggestion.
Sorry I don't get the point of these self explanatory "how to's". Not just this one but, I've seen a bunch of other videos that offer no useful tips, they just show the obvious. I mean what are people going to do, install them plaid side down?