How to implement Extent Report in Selenium Automation project ?

package MyFirstMavenProject.MavenProject;

import java.io.File;

import org.testng.Assert;
import org.testng.ITestResult;
import org.testng.SkipException;
import org.testng.annotations.AfterMethod;
import org.testng.annotations.AfterTest;
import org.testng.annotations.BeforeTest;
import org.testng.annotations.Test;

import com.relevantcodes.extentreports.ExtentReports;
import com.relevantcodes.extentreports.ExtentTest;
import com.relevantcodes.extentreports.LogStatus;

public class ExtentReportTest {

	ExtentReports extentReport;
	ExtentTest extentTest;

	@BeforeTest
	public void startTestReport() {

		// initialize ExtentReport by passing path where we store ExtentReport
		// and second parameter is Boolean replaceExting
		// replaceExting = true (new report will replace existing report)
		extentReport = new ExtentReports(System.getProperty("user.dir") + "/test-output/Extent.html", true);

		extentReport.loadConfig(
				new File(System.getProperty("user.dir") + "src/main/java/com/config/extentReportConfig.xml"));

		// To add system or environment info by using the setSystemInfo method.
		extentReport.addSystemInfo("Host Name", "Tutorials Hut");
		extentReport.addSystemInfo("User Name", "tutorialshutuser");
		extentReport.addSystemInfo("Environment", "QA");

		// Allows performing configuration and customization to the HTML report
		// from local resource as mentioned in the 'extent-config.xml'
		extentReport.loadConfig(new File(System.getProperty("user.dir") + "\\extent-config.xml"));
	}

	@Test
	public void firstTestCase() {

		// Calling startTest() generates a toggle for the test in the HTML file
		// and adds all log events under this level.
		// startTest(java.lang.String testName)
		extentTest = extentReport.startTest("FirstTestCase");
		Assert.assertTrue(true);
		// writing the log for first test case in the report
		extentTest.log(LogStatus.PASS, "FirstTestCase is passed");
	}

	@Test
	public void secondTestCase() {
		extentTest = extentReport.startTest("secondTestCase");
		Assert.assertTrue(false);
		extentTest.log(LogStatus.FAIL, "secondTestCase is failed");
	}

	@Test
	public void thirdTestCase() {
		extentTest = extentReport.startTest("thirdTestCase");
		throw new SkipException("thirdTestCase is skipped");
	}

	@AfterMethod
	public void getResult(ITestResult result) {
		if (result.getStatus() == ITestResult.FAILURE) {
			extentTest.log(LogStatus.FAIL, "Test Case Failed is " + result.getName());
			extentTest.log(LogStatus.FAIL, "Test Case Failed is " + result.getThrowable());
		} else if (result.getStatus() == ITestResult.SKIP) {
			extentTest.log(LogStatus.SKIP, "Test Case Skipped is " + result.getName());
		}

		// ends the current test and prepares to create HTML report
		extentReport.endTest(extentTest);
	}

	@AfterTest
	public void endTestReport() {

		// Appends the HTML file with all the ended tests. There
		extentReport.flush();

		// Closes the underlying stream and clears all resources
		extentReport.close();
	}

}