Make storage make sense to me

Recently realized I was running out of hard drive space and was moving files into remote storage. But I can't make any sense as to how storage is actually determined. My storage screen says I have 404.99 of 494.38 used. The info screen for my Mac HD says 88.6 is available, which isn't too far off. But then if you total the files in finder, it has 413.34 for a total in the folders, but 475.15 is used. Then on top of it, of the 88.6 available from the info screen, 76.72 is purgeable. And 475GB of 494GB is used.

Further to my confusion, when I drill down into the Users component, the folders only add up to 328GB out of 371GB