README: add build and usage instructions

README.md

@@ -14,12 +14,67 @@ The code of the version v0 is in the directory *src/*.
 
 The pseudo code of the version v1 is in the directory *pseudo-code-v1/*.
 
+## Usage
+
+This library is delivered as an NPM package and a Maven in [Gitlab Packages](
+https://gitlab.inria.fr/concordant/software/c-client/-/packages)
+(as a private registry).
+
+### NPM install
+
+Get a deploy token or personal access token from Gitlab,
+with at least the read_package_registry scope.  
+Then setup authentication:
+``` shell
+$ npm config set @concordant:registry "https://gitlab.inria.fr/api/v4/packages/npm/"
+$ npm config set '//gitlab.inria.fr/api/v4/packages/npm/:_authToken' "<deployOrPersonalToken>"
+```
+
+Install the package:
+``` shell
+$ npm i @concordant/c-client
+```
+
+And use it:
+``` typescript
+import * from @concordant/c-client;
+```
+
 ## Build project
 
-The building is managed through the use of Gradle.
+The build is managed by Gradle.
+Kotlin sources (code and tests) are compiled to JVM Bytecode
+and to Javascript as a Node.js package.
+
+`gradle assemble`:
+- compiles code and tests to JVM Bytecode;
+- compiles code and tests to Javascript (Node.js package);
+- creates a TypeScript interface
+- assembles a NPM package
+
+`gradle allTests`:
+- runs JVM test suite;
+- runs Node.js test suite in a server like manner;
+- a report containing all tests results can be found in the file
+  `build/reports/tests/allTests/index.html`.
+
+`gradle build`:
+- compiles code and test.
+
+`gradle pack`:
+- pack the NPM package
+
+`gradle publish`:
+- publish the NPM package to the Gitlab Packages registry
+  (requires authentication ; better use it via CI pipelines).
+
+`gradle dokkaHtml`:
+- creates the documentation from code comments;
+- documentation is accessible at `build/dokka/html/crdtlib/index.html`.
+See `gradle tasks` for variants other than HTML.
 
-Build depends on the C-CRDTLib Maven registry package see
-[here](https://gitlab.inria.fr/concordant/software/c-crdtlib/-/blob/master/README.md)
-how to install it.
+`gradle clean`:
+- cleans the project.
 
-*gradle build*: compiles code.
+`gradle tasks`:
+- show all available tasks with descriptions.