All cards in the cube's maybeboard count as lessons each player owns and can be learned with no limit to copies generated.
Each player chooses one when building their deck, Steel, or Sorcery.
Players who pick Steel can fill their deck with as many Artifact "basic" lands as they please.
Players who pick Sorcery can fill their deck with as many duel color taplands as they please.
The basic concept is that steel decks are optimized for crazy powerful synergies and are generally strong decks on board, whereas Sorcery decks are built around making unique and potentially complex combos through perfect mana fixing and consistant access to pay-off spells.