where get ledgerIndex (not 32bit), how get all transaction from one block?

[Relect]

xrpl-dev-portal/docs/references/http-websocket-apis/public-api-methods/ledger-methods/ledger_entry.md

Line 55 in 4200ea6

| `index` | String | The [ledger entry ID](../../../protocol/ledger-data/common-fields.md) of a single entry to retrieve from the ledger, as a 64-character (256-bit) hexadecimal string. |

It is not clear where to get the index value; the index does not match the ledger hash. And how can I get all transactions one block using this method?

you indicate that a closed block may not necessarily be included in the registry,
but there is no last ledger_validated method (analog lodger_closed & ledger_current) ?