Add instructions for enabling linea-sequencer plugin

docs/architecture/stack/index.mdx

@@ -1,6 +1,6 @@
 ---
 title: Linea software
-image: /img/socialCards/the-linea-stack.jpg
+image: /img/socialCards/linea-software.jpg
 ---
 
 import DocCardList from "@theme/DocCardList";

docs/developers/guides/run-a-node/linea-sequencer.mdx

@@ -0,0 +1,30 @@
+---
+title: Install the linea-sequencer plugin for BESU
+description: How to install and configure the linea-sequencer plugin for Besu
+image: /img/socialCards/install-the-linea-sequencer-plugin-for-besu.jpg
+---
+
+# Install `linea-sequencer`
+
+If you want to run a Linea node and use it to interact with the blockchain, rather than running a 
+'follower' node that simply keeps a local copy of the chain, then you will need to install the 
+`linea-sequencer` plugin to ensure full functionality.
+
+Specifically, the Linea-specific API methods documented in our [reference section](/developers/reference/api)
+will not work properly unless you install and configure `linea-sequencer`.
+
+## Instructions
+
+1. Go to the [`linea-sequencer` repo releases page](https://github.com/Consensys/linea-sequencer/releases)
+and download the `.jar` file for the latest release. 
+
+2. In the local Besu runtime directory (where you will run Besu from), create a directory called 
+`plugins` and place the `.jar` file there.
+
+3. In the `config-mainnet.toml` file, add `LINEA` to the list of RPC methods:
+
+ ```
+ rpc-http-api=["ADMIN","NET","ETH","WEB3","TXPOOL","LINEA"]
+ ```
+
+When you run Besu, you will see the `linea-sequencer` plugin registered during startup.

docs/developers/guides/run-a-node/use-binary.mdx

@@ -56,6 +56,19 @@ Download the genesis file and Besu configuration file.
 
 </Tabs>
 
+:::warning[Important: enable linea-sequencer]
+
+You must install and enable the `linea-sequencer` Besu plugin if you are offering RPC services or 
+hosting nodes for usage. Enabling the plugin is a requirement for using certain endpoints, such as 
+[`linea_estimateGas`](/developers/reference/api/linea-estimategas).
+
+Please see our instructions [here](./linea-sequencer) for installing the plugin.
+
+If you are simply running a node to follow the chain and its activity, rather than using it to 
+submit transactions, you do not need to install `linea-sequencer`.
+
+:::
+
 ### Step 3. Define disk space volume (optional) {#disk-space-besu}
 
 Define a volume size appropriate to your expected usage. As of March 20 2024, Besu nodes use: