Add hello world tutorial

source/mainnet/tutorials/hello-world/hello-world.rst

@@ -0,0 +1,99 @@
+.. _hello-world:
+
+====================================
+Creating your first Concordium dApp
+====================================
+
+This tutorial guides you through creating and deploying your first smart contract on Concordium. You'll create a simple **Hello World** smart contract and deploy it on the testnet.
+
+Before you start
+================
+
+Ensure you have set up your development environment by following this :ref:`tutorial <setup-env>`.
+
+Creating your first smart contract
+==================================
+
+#. Initialize a new smart contract project:
+
+   .. code-block:: console
+
+      $ cargo concordium init
+
+#. Select the **default** template when prompted, then choose an appropiate project name. The ``init`` command has now created a template smart contract and a corresponding local repository.
+
+Write the contract
+--------------------
+
+Modify ``src/lib.rs`` to create a simple message-storing contract:
+
+#. Modify the existing state structure, the new state defines the **message** variable:
+
+   .. code-block:: rust
+
+      /// The state of the smart contract.
+      #[derive(Serialize, SchemaType)]
+      pub struct State {
+          message: String,
+      }
+
+#. Modify the **init** method which initialises the **message** variable:
+
+   .. code-block:: rust
+
+      #[init(contract = "hello_world")]
+      fn init(_ctx: &InitContext, _state_builder: &mut StateBuilder) -> InitResult<State> {
+          Ok(State {
+              message: "Hello World!".to_string(),
+          })
+      }
+
+#. Modify the **receive** method by specifying **String** as the parameter type, changing it's name to be more suggestive and assigning the **input** string to the **state**:
+
+   .. code-block:: rust
+
+      #[receive(
+          contract = "hello_world",
+          name = "set_message",
+          parameter = "String",
+          error = "Error",
+          mutable
+      )]
+      fn set_message(ctx: &ReceiveContext, host: &mut Host<State>) -> Result<(), Error> {
+          let new_message: String = ctx.parameter_cursor().get()?;
+          host.state_mut().message = new_message;
+          Ok(())
+      }
+
+#. Modify the **view** function by specifying the **String** return value type and the **message** variable of the **state**
+
+   .. code-block:: rust
+
+      #[receive(contract = "hello_world", name = "view", return_value = "String")]
+      fn view(_ctx: &ReceiveContext, host: &Host<State>) -> ReceiveResult<String> {
+          Ok(host.state().message.clone())
+      }
+
+#. Build the contract:
+
+   .. code-block:: console
+
+      $ cargo concordium build
+
+   After the command runs successfully, a file called **module.wasm.v1** will be generated in the **concordium-out** folder
+
+Deploying your contract
+=======================
+
+We recommend deploying on the **testnet**, which can be done by following these steps:
+
+#. :ref:`Set up a wallet <setup-wallets-lp>`
+#. Request **testnet CCD** using the **Request** option in the wallet
+#. **Access** the `Smart Contract Deploy Tool <https://sctools.mainnet.concordium.software/>`_  in order to deploy the generated module
+#. **Click** on the button to connect to the **Browser Wallet**
+#. **Upload** the module generated in the previous section in the Step 1 section of the dApp then **click** the button to **deploy**
+#. Choose **Derive from step 1** in **Step 2**, then **click** the button to **initialise** the smart contract, a **Smart Contract Index** will be shown
+#. **Input** the index in the next step, then select the **Derive From Smart Contract Index** option
+#. Choose **view** as the **Entry Point Name**, then **click** the **Read Smart Contract** button, **"Hello World"** will be displayed
+
+Congratulations! You've now created and deployed your first smart contract on the Concordium blockchain.

source/mainnet/tutorials/index.rst

@@ -72,6 +72,7 @@ Additional Resources
    :caption: Smart Contract Tutorials
 
    setup-env
+   Hello World <./hello-world/hello-world>
    Counter <./counter/counter-contract>
    PiggyBank <./piggy-bank/index>
    wCCD <./wCCD/index>