feat(doc): SDK generation and build docs (#377)

Author: kggilmer

README.md

@@ -14,7 +14,7 @@ This repo contains the AWS SDK for Kotlin and its [public roadmap](https://githu
 
 ## Getting Started
 
-See the [Getting Started Guide](docs/GettingStarted.md)
+See the [Getting Started Guide](docs/GettingStarted.md) to learn how to use AWS SDKs in your program.
 
 ## Feedback
 
@@ -33,7 +33,8 @@ If you are interested in contributing to the AWS SDK for Kotlin, please take a l
 ### Generate SDK(s)
 
 Generated sources are not checked into the repository, you first have to generate the clients before you can build them.
-
+A [step-by-step guide](docs/generate-sdk.md) is available that demonstrates building the AWS DynamoDB service, or if 
+you have a good working knowledge of Gradle, see below:
 
 ```sh
 ./gradlew --no-daemon :codegen:sdk:bootstrap

docs/generate-sdk.md

@@ -0,0 +1,79 @@
+# Generate an AWS SDK
+
+This page describes how to generate and build an AWS SDK. Generating an SDK from source may be useful in testing fixes,
+learning how AWS SDKs work internally, or just experimentation.
+
+### NOTE
+
+This process is not necessary to use an AWS SDK, as one can simply depend on the artifacts available in 
+[Maven Central](https://search.maven.org/search?q=aws.sdk.kotlin).  See the [getting started guide](GettingStarted.md) for details.
+
+## Prerequisites
+* Git
+* Java JDK 1.8+
+
+## Generate an SDK
+
+In this example we'll build the AWS DynamoDB SDK.
+
+### Clone this repo 
+```sh
+git clone https://github.com/awslabs/aws-sdk-kotlin.git
+cd aws-sdk-kotlin
+```
+
+### Generate the SDK source
+
+Generate the DynamoDB SDK:
+```sh
+./gradlew -Paws.services=+dynamodb :codegen:sdk:bootstrap
+```
+Notice we specify the name of the service as `dynamodb`.  The names for all AWS services can be found in
+[`codegen/sdk/aws-models`](../codegen/sdk/aws-models).
+.  So for example the name used for AWS CloudFormation's model `cloudformation.2010-05-15.json` 
+would be `cloudformation`.  The date and json extension are removed.
+
+### Compile and test the generated SDK
+```sh
+./gradlew :services:dynamodb:build
+```
+Once this completes a compiled SDK for the AWS DynamoDB service has been generated.  The version will vary depending
+on whatever is the latest version in the repository.
+
+```sh
+ls services/dynamodb/build/libs      
+dynamodb-<version>.jar
+```
+
+To use this compiled SDK from another program locally, the local Maven repository can be used.  The following command 
+will publish artifacts from `aws-sdk-kotlin` to the local maven repository, including the DynamoDB service and supporting
+runtime libraries:
+
+```sh
+./gradlew publishToMavenLocal
+```
+
+## Using a locally-built SDK
+
+In order to use an SDK published to the local maven repository, the `mavenLocal()` repository must be added to the program's
+build file:
+
+```
+repositories {
+    mavenLocal()
+}
+```
+
+And then simply add the dependency:
+
+```
+dependencies {
+    implementation("aws.sdk.kotlin:dynamodb:<version>")
+}
+```
+
+## Summary
+
+This page covers building an AWS SDK using the `aws-sdk-kotlin` SDK generator. If you experience problems please [file 
+an issue](https://github.com/awslabs/aws-sdk-kotlin/issues). If you have questions or ideas about how we can improve our 
+SDKs, please join [our discussions](https://github.com/awslabs/aws-sdk-kotlin/discussions).