docs: adds contributing guide and usage examples

CONTRIBUTING.md

@@ -0,0 +1,73 @@
+# Contributing to oscal-sdk-go
+
+Thank you for your interest in `oscal-sdk-go`!
+Our project welcomes external contributions.
+
+## How to Contribute
+
+To contribute code or documentation, please submit a [pull request](https://github.com/oscal-compass/oscal-sdk-go/pulls).
+
+It is preferable that a pull request relates to an existing issue. If you find a bug or want to suggest a feature, please submit
+a GitHub [issue](https://github.com/oscal-compass/oscal-sdk-go/issues) first.
+This is not required for minor changes like typos in documentation.
+
+## Development
+
+### Run tests
+
+```bash
+make test-unit
+```
+
+### Format and Style
+
+**Requires [`golangci-lint`](https://golangci-lint.run/welcome/quick-start/)**
+
+```bash
+make format
+# For issue identification
+make vet
+# Linting
+make lint
+```
+
+## Legal
+
+Each source file must include a license header for the Apache
+Software License 2.0. Using the SPDX format is the simplest approach.
+
+e.g.
+```text
+/*
+ Copyright 2025 The OSCAL Compass Authors
+ SPDX-License-Identifier: Apache-2.0
+*/
+```
+
+### Sign your work
+
+We have tried to make it as easy as possible to make contributions. This
+applies to how we handle the legal aspects of contribution.
+
+We use the same approach - the [Developer's Certificate of Origin 1.1 (DCO)](https://oscal-compass.github.io/compliance-trestle/latest/contributing/DCO/) - that the Linux® Kernel [community](https://developercertificate.org/)
+uses to manage code contributions.
+
+We simply ask that when submitting a patch for review, the developer
+must include a sign-off statement in the commit message.
+
+Here is an example Signed-off-by line, which indicates that the
+submitter accepts the DCO:
+
+```text
+Signed-off-by: John Doe <[email protected]>
+```
+
+You can include this automatically when you commit a change to your
+local git repository using the following command:
+
+```bash
+git commit --signoff
+```
+
+Note that DCO signoff is enforced by [DCO bot](https://github.com/probot/dco). Missing DCO's will be required to be rebased
+with a signed off commit before being accepted.

README.md

@@ -1,5 +1,9 @@
 # oscal-sdk-go
 
+[![Go Report Card](https://goreportcard.com/badge/github.com/oscal-compass/oscal-sdk-go)](https://goreportcard.com/report/github.com/oscal-compass/oscal-sdk-go)
+[![GoDoc](https://img.shields.io/static/v1?label=godoc&message=reference&color=blue)](https://pkg.go.dev/github.com/oscal-compass/oscal-sdk-go)
+[![OpenSSF Scorecard](https://api.scorecard.dev/projects/github.com/oscal-compass/oscal-sdk-go/badge)](https://scorecard.dev/viewer/?uri=github.com/oscal-compass/oscal-sdk-go)
+
 `oscal-sdk-go` complements the `compliance-trestle` SDK by providing the core SDK functionality in Go.
 
 > WARNING: This project is currently under initial development. APIs may be changed incompatibly from one commit to another.
@@ -8,33 +12,73 @@
 
 Below is a table to show what is currently supported by the SDK.
 
-| SDK Functionality                         | Supported |
-|-------------------------------------------|-----------|
-| OSCAL Types with Basic Trestle Extensions | ✓  |
-| OSCAL Schema Validation                   |           |
-| Target Components Extension               |           |
-| Multiple Parameters per Rule              |           |
-| OSCAL to OSCAL Transformation             | ✓  |
-| OSCAL Constraints Validation              |           |
+| SDK Functionality                         | Supported          |
+|-------------------------------------------|--------------------|
+| OSCAL Types with Basic Trestle Extensions | :heavy_check_mark: |
+| OSCAL Schema Validation                   | :x:                |
+| Target Components Extension               | :x:                |
+| Multiple Parameters per Rule              | :x:                |
+| OSCAL to OSCAL Transformation             | :heavy_check_mark: |
+| OSCAL Constraints Validation              | :x:                |
+
+
+## Get Started
 
-## Run tests
+Add the module as dependency to your project:
 
-```bash
-make test-unit
+```console
+go get github.com/oscal-compass/oscal-sdk-go
 ```
 
-## Format and Style
+### SDK Terms
+
+[`Extensions`](https://github.com/oscal-compass/oscal-sdk-go/tree/main/extensions): `oscal-compass` uses OSCAL properties to [extend](https://pages.nist.gov/OSCAL/learn/tutorials/general/extension/#props) OSCAL.  
+[`Rules`](https://github.com/oscal-compass/oscal-sdk-go/tree/main/rules): Rules are associated with Components and define a mechanism to verify the proper implementation of technical controls.  
+[`Settings`](https://github.com/oscal-compass/oscal-sdk-go/tree/main/settings): Settings define adjustments to fine-tune pre-defined options in Rules for the implementation of a specific compliance framework.  
+
+### Perform a Transformation
+
+```go
+import (
+	...
+	oscalTypes "github.com/defenseunicorns/go-oscal/src/types/oscal-1-1-2"
 
-**Requires [`golangci-lint`](https://golangci-lint.run/welcome/quick-start/)**
+	"github.com/oscal-compass/oscal-sdk-go/generators"
+	"github.com/oscal-compass/oscal-sdk-go/transformers"
+)
 
-```bash
-make format
-# For issue identification
-make vet
-# Linting
-make lint
+func main() {
+	file, err := os.Open("path-to-my-compdef")
+	if err != nil {
+		log.Fatalf("failed to open component definition, %v", err)
+	}
+	definition, err := generators.NewComponentDefinition(file)
+	if err != nil {
+		log.Fatalf("failed to read component definition, %v", err)
+	}
+
+	if definition != nil {
+		assessmentPlan, err := transformers.ComponentDefinitionsToAssessmentPlan(context.Background(), []oscalTypes.ComponentDefinition{*definition}, "example-framework")
+		if err != nil {
+			log.Fatalf("failed to create assessment plan, %v", err)
+		}
+		assessmentPlanJSON, err := json.MarshalIndent(assessmentPlan, "", " ")
+		if err != nil {
+			log.Fatalf("failed to marshal assessment plan, %v", err)
+		}
+		fmt.Println(assessmentPlanJSON)
+	}
+}
 ```
 
-# Acknowledgments
+## Contributing
+
+Our project welcomes external contributions. Please see `CONTRIBUTING.md` to get started.
+
+## Code of Conduct
+
+Participation in the OSCAL Compass community is governed by the [Code of Conduct](https://github.com/oscal-compass/community/blob/main/CODE_OF_CONDUCT.md).
+
+## Acknowledgments
 
 This project leverages [`go_oscal`](https://github.com/defenseunicorns/go-oscal) to provide Go types for the OSCAL schema.