Yes, you are indeed rigth. For Selenium WebDriver testing on servers or on machines where you do not have a GUI, use either HTMLUnit Driver or PhanthomJS driver. So you will have to similarly download the driver.exe from SeleniumHQ's website, provide the path in your code and most importantly import the required packages in your code. For python, you will do it something like this:
from selenium import webdriver
dr = webdriver.PhantomJS()