moves content to transactions page

polkadot-protocol/basics/blocks-transactions-fees/blocks.md

@@ -1,4 +1,35 @@
 ---
 title: Blocks
 description: TODO
----
+---
+<!--######This is a WIP page#######-->
+
+<!--
+# Blocks
+
+## Introduction
+
+
+
+## What is a Block?
+
+In the Polkadot SDK, a block consists of a header and an array of transactions. The header contains the following properties:
+
+- **Block height** - the number of blocks that have been created in the chain
+- **Parent hash** - the hash of the previous block in the chain
+- **Transaction root** - a cryptographic digest of the transactions in the block
+- **State root** - a cryptographic digest of the state after executing the transactions
+- **Digest** - a list of additional information that can be included in the block
+
+All transactions are bundled together as a series to be executed as defined in the runtime. You'll learn more about transaction ordering in the [Transactions Lifecycle](/polkadot-protocol/protocol-components/transactions/transactions-lifecycle/){target=\_blank} documentation. The transaction root is a cryptographic digest of this series. This cryptographic digest serves two purposes:
+
+- It prevents any alterations to the series of transactions after the header has been built and distributed
+- It enables light clients to succinctly verify that any given transaction exists in a block given only knowledge of the header
+
+## Where to Go Next
+
+Now that you are familiar with the information that constitutes a block, you can explore the following topics to learn more:
+
+- [**Block reference**](https://paritytech.github.io/polkadot-sdk/master/sp_runtime/traits/trait.Block.html){target=\_blank} - learn more about the block structure in the Polkadot SDK runtime
+
+-->