We have to apply for the internship with letters of recommendation, statement of purpose and curriculum vitae at their website. Then they select the candidate and contact him/ her through email. They ask the candidate to send the needed documents like copy of passport and a few other documents (like bank account statement, copy of health insurance etc.), following which the visa processing begins, and the university sends required documents to the candidate through mail/ shipping. After that, the candidate can apply for the visa and if approved, goes off to work in the US for the required length of time.