What should I do along side WK?

It’s really going to depend on what you’re interested in and what you expect to get out of WK. Assuming you’re a complete beginner to Japanese this would be a good time to look into an introductory textbook (or equivalent resource, eg. Bunpro).

If you want to dip your toes into absolute beginner reading that’s kind of level appropriate try

And if you want harder reading something like the book clubs