How Can An Employment Based Green Card Holder Help His Family Obtain Green Cards?

I received my green card through my job. My boss says that he will help me to bring my wife and children to come live with me here in the U.S. How do we accomplish this?
As long as you were married to your wife prior to obtaining your green card, and as long your children are unmarried and under 21 years old, and the visa number remains current, you may file for them as "following to join." However, if you married after obtaining your green card or the children were born after obtaining your green card, you will need to file the Alien Relative petition, and they will have to wait for visa numbers to become available according to the priority/filing date.