I had a look at it recently because I'm a second language teacher, and it's a shambles. If there's one thing I've learned in 10 years of teaching foreigners English, it's that there's absolutely no link between knowing the names for bits of grammar and being able to actually use it. Unfortunately, the test doesn't check their ability to use the language, just whether they can label bits of grammar.
One of the most effective things you can do for kids' writing is give them silent reading time with a book they've chosen (not one that has been chosen for them because it has particular grammar points in it). Unfortunately, not enough teachers do this because they feel like it's not doing their job to just sit there while the kids read by themselves. But for parents in lockdown, that's exactly what they should have been recommending. Get down to the charity shop and let them pick a few books out.