I posted this question in the beta testing section a few days back and haven’t heard anything. I’ve been out of the v.3 for Windows loop for a while and was trying to lend some testing help. Can anyone here shed some light?
"Hey all!
If I were to download the latest beta, is there a particular feature, set of features (ie. compiling), that I should focus on trying to test, or is a more overall testing still needed?"
The best thing to do is to take a look at the release notes posted to the most recent build. This is going to be a list of all of the areas of the code that has changed recently, and in the case of new features, stuff that hasn’t yet been heavily tested outside of internal testing.
The release notes are always posted right below the download links. Think of them like a checklist of things to test, if that’s what you want to do! Unfortunately a lot of these notes are kind of vague and not really described well—but we’re not expecting anyone to be thorough. 
If it doesn’t make sense just skip it and move on.
Off the top of my head though, one thing that could use some testing right now is what they recently added: Ctrl+F on the Corkboard and Outliner. You can now search for cards/rows like a filter. Testing that from various contexts, with different types of cards, with different layouts and viewing options and so on, is an example of good testing. For some newly added features like that, you may want to keep the Mac documentation handy, to see how it is meant to be used and what to expect of the feature.
Thank you, very much for the reply! I’m off to explore