@Pom *******
@Sunida *************
Sunida, I am now going through this process and it is exactly the steps you need.
I just want to add that the since the US (federal) State Department stamp in step #3 is in DC, you can (have to?) use the Thai Embassy in DC to certify that stamp, not your closest Thai consulate.
I am currently working with a service called Monument Visa (
*************************
or
@https://www.faceboo*******************
) that offers a Thailand document legalization service. I went to my local county and got the certified copy of the license and then took it to my state's Secretary of State for the authentication stamp. Then I mailed it to Monument Visa who will walk it into the State Department (2-3 weeks instead of 6+) and then pick it up and walk it over to the Thai Embassy, then pick it up and mail it to me. Saves time and hassle, and worth the extra costs ($125 less fees, so actually pretty reasonable).
Good luck!