Google AdWords Keyword Research

My company offers a service that helps students studying in the US on F-1 student visas find permanent residency visas through employment sponsorship after they graduate. They receive a green card through this program. Currently no company exists that does this specific service except us, so the competition is relatively low. I have a very specific but large demographic of people I am trying to reach through Google AdWords. This group is international students studying in the United States on F-1 student visas at the undergraduate and graduate level. The size of this demographic is estimated around 1.2 million people. We are trying to find the ones that want to live and work permanently in the United States after they graduate. OPT (Optional Practical Training) is a period during which undergraduate and graduate students with F-1 status who have completed or have been pursuing their degrees for more than nine months are permitted by the United States Citizenship and Immigration Services (USCIS) to work for one year on a student visa towards getting practical training to complement their education. Our target demographic is searching a lot about this because often, this is their only option to remain in the United States after they graduate. This is basically an extension of the F-1 visa, however, once expired, unless these students can find employer sponsors for a visa, they will be forced to return to their home country. OR they are among the select few that apply for H1 Visas but, these are temporary visas and not Permanent Visa like the EB3 visa our employers are sponsoring for. The H visas also usually require work experience that these recent graduates do not have.