Update CONTRIBUTING.md

CONTRIBUTING.md

@@ -107,7 +107,7 @@ Command | Description
 `mvn clean install -Dmaven.test.skip=true` | Build and install the artifacts into the local repository, without running any of the unit tests.
 `mvn clean install -P ballerina` | The `ballerina` profile is used to build only the modules necessary for the runtime distribution (i.e., excluding the tools, etc.)
 
-Extract the Ballerina distribution created at `distribution/zip/ballerina/target/ballerina-<version>-SNAPSHOT.zip`.
+Extract the Ballerina distribution created at `distribution/zip/ballerina/target/ballerina-<version>-SNAPSHOT.zip`. The `zip/ballerina` directory contains the runtime only. `zip/ballerina-tools/` contains the runtime and tools (e.g., Ballerina Composer).
 
 ### Setting up your development environment