selenium_code.java

/* Clicks an element */
driver.findElement(By.id("some-button")).click();             

/* Write some text on the element */
driver.findElement(By.id("user-name")).sendKeys("Some text");

/* Clicks a link with the text "Download free" */
driver.findElement(By.linkText("Downwload free")).click();

/* Make it wait for some time until something you defined happens like the presence of an element */
(new WebDriverWait(driver, WAIT_SECONDS)).until(ExpectedConditions.presenceOfElementLocated(By.id("vote-for-prettiest-dog-button")));