Add tutorial for building and running hello-world.wasm (#1285)

* Add tutorial for building and running hello-world.wasm

* Fix issues with directory trees in last commit

* Add more information on various ways of creating .wasm files and running them with Wasmtime

* Fix internal links and add more information on Wasmtime CLI installation

docs/tutorial-create-hello-world.md

@@ -1,3 +1,63 @@
 # Creating `hello-world.wasm`
 
-... more coming soon
+There are a number of ways to create `.wasm` files but for the purposes of this
+tutorial, we'll be using the Rust toolchain. You can find more information on
+creating `.wasm` files from other languages in the
+[Writing WebAssembly section](./wasm.md).
+
+To build WebAssembly binaries with Rust, you'll need the standard Rust toolchain.
+
+[Follow these instructions to install `rustc`, `rustup` and `cargo`](https://www.rust-lang.org/tools/install)
+
+Next, you should add WebAssembly as a build target for cargo like so:
+
+```sh
+$ rustup target add wasm32-wasi
+```
+
+Finally, create a new Rust project called 'hello-world'. You can do this by running:
+
+```sh
+$ cargo new hello-world
+```
+
+After that, the hello-world folder should look like this.
+
+```text
+hello-world/
+├── Cargo.lock
+├── Cargo.toml
+└── src
+   └── main.rs
+```
+
+And the `main.rs` file inside the `src` folder should contain the following rust code.
+
+```rust
+fn main() {
+    println!("Hello, world!");
+}
+
+```
+
+Now, we can tell `cargo` to build a WebAssembly file:
+
+```sh
+$ cargo build --target wasm32-wasi
+```
+
+Now, in the `target` folder, there's a `hello-world.wasm` file. You can find it here:
+
+```text
+hello-world/
+├── Cargo.lock
+├── Cargo.toml
+├── src
+└── target
+   └── ...
+   └── wasm32-wasi
+      └── debug
+         └── ...
+         └── hello-world.wasm
+
+```

docs/tutorial-run-hello-world.md

@@ -1,3 +1,28 @@
 # Running `hello-world.wasm` with Wasmtime
 
-... more coming soon
+## Installing Wasmtime
+
+The Wasmtime CLI can be installed on Linux and macOS with a small install
+script:
+
+```sh
+$ curl https://wasmtime.dev/install.sh -sSf | bash
+```
+
+You can find more information about installing the Wasmtime CLI in the
+[CLI Installation section](./cli-install.md)
+
+## Running `hello-world.wasm`
+
+There are a number of ways to run a `.wasm` file with Wasmtime. In this
+tutorial, we'll be using the CLI, Wasmtime can also be embedded in your
+applications. More information on this can be found in the
+[Embedding Wasmtime section](./embed.md).
+
+If you've built the `hello-world.wasm` file (the instructions for doing so are in the
+[previous section](./tutorial-create-hello-world.md)),
+you can run it with Wasmtime from the command line like so:
+
+```sh
+$ wasmtime target/wasm32-wasi/debug/hello-world.wasm
+```