docs(readme): add package instructions to readme (#184)

* docs(readme): add info to code snippets

* docs(readme): add package info to readme

Author: y-lakhdar

README.md

@@ -65,6 +65,111 @@ To install the updated project files, build the Maven project:
 mvn install
 ```
 
+## Building from Source (Manual Build)
+
+If you want to build the library from source and share it with someone without publishing to Maven, follow these steps:
+
+### Prerequisites
+
+- Java 11 or higher
+- [Apache Maven](https://maven.apache.org/install.html) 3.6+
+
+### Step 1: Clone the Repository
+
+```bash
+git clone https://github.com/coveo/push-api-client.java.git
+cd push-api-client.java
+```
+
+### Step 2: Build the JAR
+
+```bash
+mvn clean package -DskipTests
+```
+
+This will generate the following files in the `target/` directory:
+
+- `push-api-client.java-<version>.jar` — The compiled library
+- `push-api-client.java-<version>-sources.jar` — Source code (for IDE integration)
+
+### Step 3: Install to Local Maven Repository (Optional)
+
+If you want to use the library in another local Maven project:
+
+```bash
+mvn clean install -DskipTests
+```
+
+This installs the JAR to your local `~/.m2/repository`, making it available to other projects on your machine.
+
+### Step 4: Share the JAR
+
+To share the built JAR with someone else:
+
+1. **Send the JAR file**: Share the `target/push-api-client.java-<version>.jar` file directly.
+
+2. **Recipient adds JAR to their project**:
+
+   **Option A — Install to their local Maven repository:**
+
+   ```bash
+   mvn install:install-file \
+     -Dfile=push-api-client.java-<version>.jar \
+     -DgroupId=com.coveo \
+     -DartifactId=push-api-client.java \
+     -Dversion=<version> \
+     -Dpackaging=jar
+   ```
+
+   Then add the dependency to their `pom.xml`:
+
+   ```xml
+   <dependency>
+     <groupId>com.coveo</groupId>
+     <artifactId>push-api-client.java</artifactId>
+     <version><version></version>
+   </dependency>
+   ```
+
+   **Option B — Use system scope (not recommended for production):**
+
+   ```xml
+   <dependency>
+     <groupId>com.coveo</groupId>
+     <artifactId>push-api-client.java</artifactId>
+     <version><version></version>
+     <scope>system</scope>
+     <systemPath>${project.basedir}/lib/push-api-client.java-<version>.jar</systemPath>
+   </dependency>
+   ```
+
+   **Option C — For Gradle projects:**
+
+   Place the JAR in a `libs/` folder and add:
+
+   ```groovy
+   dependencies {
+       implementation files('libs/push-api-client.java-<version>.jar')
+   }
+   ```
+
+### Running Tests
+
+To run the test suite:
+
+```bash
+mvn test
+```
+
+### Validating Code Format
+
+Before contributing, ensure your code follows the project's formatting rules:
+
+```bash
+mvn spotless:check    # Check formatting
+mvn spotless:apply    # Auto-fix formatting issues
+```
+
 ## Usage
 
 > See more examples in the `./samples` folder.