Crazy Dave Squad achievement in Plants vs. Zombies Garden Warfare

This Achievement should come naturally with gameplay progression. You can level your plant class by completing set challenges. Challenges can be found when selecting a plant class before starting a match.

If you're having trouble with any set challenges you can use challenge skip stars to automatically complete selected challenges. Challenge skip stars can be obtained via sticker shop. I've found the best chance of getting these is through the pack worth 10,000.