XPath of an element in HTML code

There is a simple locator that fits this use case perfectly:

driver.findElement(By.linkText("Select")).click();

Note that instead of driver in this case, there can be a WebElement used, for example, imagine you've already found a product and want to "select" it:

WebElement product = driver.findElement(By.cssSelector("div.product")); 
product.findElement(By.linkText("Select")).click();

I need to click the 'Select' button only if the product name is BYOX Samsung S6 White in above div class. how can i do this ?

Sure:

WebElement product = driver.findElement(By.xpath("//div[contains(@class, 'product') and h3 = 'BYOX Samsung S6 White']"));
product.findElement(By.linkText("Select")).click();

There are two select elements (one is the big image the other the Select-link) Do you mean the second element?

Xpath:

//div[@class='cta']/a[@class]

Css:

div.cta a.select-device-button

(similar but more efficient in Selenium and in my opinion easier to declare)

If you wanted the first element in both cases just leave out the declaration for the div element.

In Firefox you can easily try out locators and it is always a bit depending how strict or flexible you want to keep them.

To the edited point:

You might check independently for the value of the hidden input field (it seems here is no parsing necessary) and is not dependent on the localisation. Alternatively check the header element or the image reference.

You don't have to use xpath. Simpler way will be using other locators. You can use

• className

  WebElement button = driver.findElement(By.className("btn"));
  WebElement button = driver.findElement(By.className("btn-sml"));
  WebElement button = driver.findElement(By.className("select-device-button"));
  

• linkdText

  WebElement button = driver.findElement(By.linkText("Select"));
  

• cssSelector

  WebElement button = driver.findElement(By.cssSelector(".btn.btn-sml.select-device-button"));
  

Each one of those can give you the button element.