hey Wayne! great questions, and I think @costip is doing a great job replying so far! I would add a few things: "miniblocks" are just logical arrangements of transactions inside a block. They are important because a hash of the miniblocks is "notarized" (validated, attested) by the metachain. But the transactions are executed in the respective shards. Let's say you send a transaction from shard 1 to shard 2, -5 EGLD in Address shard 1, +5 EGLD in Address shard 2. The transaction will be first executed in Shard 1, where Address Shard 1 will have a new balance, let's call it balance 1, which is balance 0 - 5 EGLD. This transaction is included in Miniblock 2, which contains the transactions originating in Shard 1, aimed at Shard 2. The Metachain makes a note of this miniblock (notarizes its hash), thus confirming the Shard 1 transaction (balance change for Address Shard 1) valid Shard 2 now processes the transaction on its end: it sees the transaction, it sees the metachain confirmed its processing on Shard 1, so it then proceeds to change the balance for Address Shard 2: balance 0 + 5 EGLD. Shard 2 also includes this transaction in Miniblock 1, which is also notarized by the Metachain, thus making the transaction valid & final. Makes sense?