docs: update docs after cli init command was added

Author: esynr3z

docs/changelog.md

@@ -34,6 +34,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - CLI command `corsair check` to validate input files
 - CLI command `corsair schema`  to generate JSON-schemas of input files for IDE hints, autocompletion and validation
 - CLI command `corsair build`  to render outputs
+- CLI command `corsair init`  to initialize a new project
 - `BuildSpecification` data model to store build targets and configuration
 - Register map data models (`Map`, `Register`, `Field`, `Enum`, `EnumMember`) for internal CSR representation
 - `SetializedParser` to parse register map from JSON/YAML/HJSON files

docs/first-steps.md

@@ -4,4 +4,26 @@ icon: octicons/mortar-board-16
 
 # First Steps
 
-TODO
+After completing the installation as described in the [Installation guide](./installation.md), you can create a new project and build it.
+
+You can quickly create a new project using the [`corsair init`](./cli.md#corsair-init) command:
+
+```bash
+corsair init
+```
+
+This command will create two files in the current directory: `csrmap.yaml` and `csrbuild.yaml`.
+
+The first file, `csrmap.yaml`, describes the source CSR map. It contains the definitions of your registers and their fields. The second file, `csrbuild.yaml`, is the build file. It specifies how to process the `csrmap.yaml` and what output files (like RTL code, software headers, or documentation) should be generated.
+
+Once you have your register map defined and the build file configured, you can generate the output files using the [`corsair build`](./cli.md#corsair-build) command:
+
+```bash
+corsair build
+```
+
+This command will process your input files according to the `csrbuild.yaml` specification and place all generated artifacts into the `corsair-build` directory by default.
+
+To learn more about the underlying principles of Corsair, refer to the [Workflow](./concepts/workflow.md) section in our concepts guide.
+
+For detailed information on the formats of the input files, please see the [Build File](./build-file/index.md) and [Register File](./register-file/index.md) documentation.