This is the US fiancee visa process. If you are applying to take your fiancee back to the US then the processes should be reasonably easy. These are the basics of the K1 visa process and the steps which do get followed. Speak to a lawyer if you are not certain about anything.
US Fiancee Visa Process
To start the K1 Visa process you need to complete the application on Form I-129F which is a ‘Petition for Alien Fiancee‘ with the USCIS office in your area or which covers your area. This application cannot be started abroad and must be filed in the US. One exception is in Bangkok where if you are a permanent resident of Thailand the US Embassy in Thailand would be allowed to accept the application.
Once this is filed you are sent a receipt of application. This is called the Notice of Action 1 and serves as your receipt of the application. Once it has been approved you will receive another letter. This stating that it has been approved and this is called the Notice of Action 2. From here they send the completed application to the National Visa Center. Then once they have approved it it is then sent to the US Embassy where your fiancee resides and the US Embassy will then contact her directly for an interview.
You will note that there is also a medical exam that needs to be completed. It is always best to ask a US immigration lawyer the matter. Mistakes are very easy and this can create delays or worst get a visa denial. The cost of a visa denial is going to cost more than the initial application for the visa. Seek advice for your US fiancee visa process.