The first steps are: File Form 1-130, Petition for Alien Relative, Provide proof of your legal status in the U.S., submit proof of your relationship. If you are a member of the military, special conditions may apply to your situation.
When petitioning for your relative, the following preference categories apply:
•First preference: Unmarried, adult sons and daughters of U.S. citizens. (Adult means 21 or older)
•Second Preference (2A): Spouses of green card holders, unmarried children (under 21) of permanent residents
•Second Preference (2B): Unmarried adult sons and daughters of permanent residents
•Third Preference: Married sons and daughters (any age) of U.S. citizens
•Fourth Preference: Brothers and sisters of adult U.S. citizens
A visa becomes available to a preference category according to the priority date (the date the I-130 was properly filed).