Better testnet instructions in readme

README.md

@@ -7,7 +7,7 @@ A Proof of Work blockchain node for use in the Polkadot Blockchain Academy.
 It happens to be based on Substrate, but no Substrate knowledge is required.
 Students will use this node to start their own network, perform hard and soft forks, and execute smart contracts.
 
-Instructors, planning to host such an activity should see the docs on [setting up a bootnode](./SettingUpTheBootnode.md).
+Instructors, planning to host such an activity should see the docs on [setting up a bootnode](./SettingUpTheBootnode.md). TODO Expand that doc into a full guide to running the workshop.
 
 ## Building the Node
 
@@ -16,6 +16,70 @@ First you will need a [Substrate developer environment](https://docs.substrate.i
 1. Cloning this repo
 2. Running `cargo build --release`
 
+TODO show how to use `--mining-account-id` to mine to different accounts.
+
+## Run a Single Development Node
+
+You can use a native binary if you built it in the previous section. Otherwise you can use a Docker.
+
+```sh
+./target/release/academy-pow --dev
+```
+
+### Docker Single Node
+
+If you use docker, you need to map the RPC port and specify `--rpc-external` so that the node listens on `0.0.0.0`. Or something like that....
+
+Networking can be challenging for new Docker users, like me. If you are on linux, you may prefer to use `--network host` which allows the containerized node to operate directly on the local network. Consult the Docker docs for more details.
+
+```sh
+docker run -p 9944:9944 ghcr.io/polkadot-blockchain-academy/academy-pow:main --dev --rpc-external
+```
+
+## MultiNode Testnet
+
+When using the local networking, you can use the `--discover-local` flag to discover peers on your local network.
+
+```sh
+# Start the first node.
+# Same as a single node network above.
+./target/release/academy-pow --dev --mining-algo keccak
+
+# Start the second node
+# Choose a non-default rpc port because the default port is taken by the first node.
+./target/release/academy-pow --dev --mining-algo sha3 --rpc-port 9955 --discover-local
+```
+
+### Docker Multi Node
+
+With Docker, we can't rely on local peer discovery. Instead, copy the bootnode address from the logs of the first node.
+Look for a line like this
+
+```
+🏷  Local node identity is: 12D3KooWR2y4tUSpqrPgvSoqfcx9bT8aV2LwHR3BJkWJFTBjZMbZ 
+```
+
+```sh
+# Start the first node.
+# Same as a single node network above.
+docker run -p 9944:9944 ghcr.io/polkadot-blockchain-academy/academy-pow:main \
+    --dev \
+    --mining-algo keccak \
+    --rpc-external
+
+# Start the second node.
+# Publish all exposed ports to RANDOM ports on the host.
+# Specify the bootnode address you copied from the first node
+docker run --publish-all ghcr.io/polkadot-blockchain-academy/academy-pow:main \
+    --dev \
+    --mining-algo sha3 \
+    --rpc-external \
+    --bootnodes /ip4/127.0.0.1/tcp/30333/p2p/12D3KooWR2y4tUSpqrPgvSoqfcx9bT8aV2LwHR3BJkWJFTBjZMbZ
+
+```
+
 ## More Help
 
-This code will be used primarily as an in-class activity that is instructor led, so just wait for details in class.
+```sh
+academy-pow --help
+```