The coaches have answered this in broad terms before (if you search “VK” in the search bar you will get some responses in previous threads) but the most relevant response is probably here: https://uphillathlete.com/forums/topic/is-vk-training-any-different/
TL;DR Aerobic base is still extremely important and you should start with the basic principle of ensuring that your AeT/AnT spread is less than 10% and that you should introduce some Z3/Z4 at around 5-10% of your weekly volume.
Taking a step back and thinking about this more broadly, it’s always worth examining the races you are training for and what attributes you would require for a positive outcome and comparing this to your current strengths and weaknesses.
As an example, I currently live in a very flat city but I am training for a fairly steep FKT that is 21km w/ 1000m vert. Therefore, the ME workouts in Mike Foote’s Big Vert plan have been an enormous aid as I lack access to hills or mountains with decent vertical gain.
If I was training for a less steep or less technical race, I would probably shift my training more towards the Z3/Z4 workouts in a weekly cycle (see Luke Nelson’s 50km Plan). Again, it will all depend on the requirements for your races.