To start a node using default parameters, run the following command from a command line shell or console. Let's assume that we have downloaded version 2.39.0.
java -jar selenium-server-standalone-2.39.0.jar -role node -hub http://localhost:4444/grid/register
This assumes that Selenium Grid hub has been started on the local computer with the port 4444. The default port of the hub uses to listen for new request is port 4444. This is why port 4444 was used in the URL for locating the hub.
If you get any connection error, be sure to turn off the firewalls on the machines running your hub and nodes.