It's just the documentation that is to be done. You can use it already. There are some quick examples in the YouTube video in these three sections:
01:10 Everything
04:28 Find As You Type
08:45 Find Files
The search field that used to only be for Windows Search now has multiple modes, including Everything if it's installed.
You can type a + into the file display to enter an Everything query there as well.
And it can be used in a few other places/ways. Also makes folder sizes appear right away.
If you're using Everything 1.5 you need to set alpha_instance=0 in its config file to make Opus see it, since we use the 1.4 API while 1.5 is still in alpha. Other threads explain this better than I can as I've not done it myself; just search here for alpha_instance if you need the details.