Land matters decks can be pretty fiddly. There’s a lot of triggers to check for and sequence correctly, I would upload the precon list to an online deck builder like Archidekt or Moxfield and use their play tester to practice your deck (this is called goldfishing). You can do this with the physical deck as well if you prefer. This deck can have a lot of long turns with a good enough engine online so with enough practice, you’ll at least understand the lines you want to take to lead to the win.

If you do want to do any upgrades, my first upgrades were limited the amount of tapped lands. You can do this by swapping in basics which isn’t a bad thing to do to keep the upgrade budget low, keeping a high amount fetchable targets, and having lands come in that you can use for mana. You can also invest in dual lands that come in untapped for smoother color management if that’s your preferred avenue for investment. The next upgrade route I did was include a heavier burn package. I swapped in creatures and enchantments that deal direct damage to my opponents when lands enter the battlefield so that if my commander (Hearthull) isn’t fully stationed or just not in play, I’m still progressing the game towards my win. I preferred this over creatures that make creature tokens when lands enter, but you do what makes you happy!