Answers for "nodes and hubs in selenium grid"

selenium grid configuration

java -jar selenium-server-standalone-2.53.1.jar -role hub -hubConfig hubconfig.json

nodes and hubs in selenium grid

-we run this jar from 2 roles: hub and node
-hub receives commands Webdriver object of the client
-then hub is looking for available nodes 
 for execution.
-nodes are executing tests

how to configure selenium grid to driver

I configure my driver class to run remote test.
DesiredCapabilities.desiredCapabilities = new DesiredCapabilities();
desiredCapabilities.setCapability("browser","chrome");
URL gridUrl = new URL("http://ipAdress.4444/wd/hub");
driverPool.set(new RemoteWebDriver(gridUrl, desiredCapabilities));