1. You will have to apply online on FBI website and pay the fee for FBI Identity History Summary check.
2. You will have to get someone professional to take your fingerprints on FD-258 card. Include more than one card so that if prints are not clear on one card, FBI can use the prints on the other one. If you send only one card with unclear fingerprints, FBI will reject your application.
3. You will have to physically mail the card(s) and the confirmation email that you got to the FBI in the US.
4. Wait till the your mail reaches FBI and they get to your fingerprints. All the process might take about 15 business days or more so be patient. All the best!