You have to install Java Runtime Environment 8 to use this package. JRE is required to run the Selenium server. The JRE 9 is the latest, but it tend to have problem with Selenium.
You have to run the Selenium sever before using this package. Selenium Standalone Server is available at SeleniumHQ. This repository also contains Selenium Standalone Sever (selenium-server-standalone-3.4.0.jar) in a sub-directory for download, but not a web driver for Firefox (geckodriver). Please download geckodriver and save it to the same directory as the Selenium server.
To start Selenium Standalone Sever, you only need to run the following command in the console:
java -jar selenium-server-standalone-3.4.0.jar
Sometimes, you have to tell Selenium the location of geckodriver (in the same directory, in this example):
java -jar -Dwebdriver.gecko.driver=./geckodriver selenium-server-standalone-3.4.0.jar
On Windows, the command looks slightly different:
java.exe -Dwebdriver.gecko.driver=./geckodriver.exe -jar selenium-server-standalone-3.4.0.jar
Note that you have the directory that contains Java executable in the system path. On Windows, java.exe is usually located in C:\Program Files (x86)\Java\jre1.8.0_144\bin. Please refer to other source for how to add a directory to the system path. After adding to the system path, your Windows needs restart.
You can stop the Selenium server by pressing Ctrl + C.