The first ledger is the block lattice - every Zenon address builds it's own account chain as it sends and receives transactions, where every transaction is a block. This allows account chains to update individually and independently and enables for many actions at the same time.

The second ledger on Zenon is the Meta-Dag. It consists of meta-blocks called Momentums produced by consensus nodes named Pillars.

All transactions on the network consist of account blocks.

When I send you some tokens my account adds a send block to its chain. It broadcasts this change to the network.

Pillars are continually packing momentums, confirming blocks and publishing the record to the Meta-Dag.

When a Pillar confirms the send block it will then reciprocate and create a receive block to add to your account chain.