From the month of October 2016 winners of the DV-2017 are being called for the visa interview according to the winners' case numbers.
In this interview the DV-2017 winners must proof their eligibility to get their American immigrant visas that can help them to get their LPR status in the USA which is also called as American Green card.
Lower rank case numbers will be called for the interview first and will continue in that order till the visas exhaust or till to the official closing date of 30th September 2017. Meanwhile higher rank case numbers may not be called for the interview as the visas may exhaust prior to the closing date of the program. For example in the DV-2016 American visa lottery program nearly all the visas are exhausted in the month of August 2016.
Selected winners under the DV-2017 visa lottery program while staying in the USA can contact the USCIS office to submit their petition to change their current status to America LPR status through normal immigrant processing.
Source: U.S State Department