Here’s how it works. It might be the case that the icons on your Mac aren't showing up properly, something that's easily fixable with a quick Terminal command. After updating to iWork 13 ...

An icon in the shape of a lightning ... open your Mac's Terminal If you plan on using the Terminal a lot, it's a good idea to pin it to your computer's bottom toolbar (the "dock") for easier ...

Scroll through the list of apps till you find the Terminal icon, as shown by the arrow in ... you should have seen the Mac desktop go away and then start again. This was the Finder restarting ...