Student-level files are currently available for the Base Year (2009), First Follow-up (2012), 2013 Update collection (2013), High School Transcripts (2013-2014), Second Follow-up (2016) and a school-level file is available for the Base Year.
See our HSLS Variable List (932 KB) to determine which file(s) have the variables you’re looking for.
Public-use data is available for immediate download, here: http://nces.ed.gov/onlinecodebook
Restricted-use data is available under restricted-use license. Find out more about how to obtain a restricted-use license, here: http://nces.ed.gov/statprog/instruct.asp
We also recommend reviewing the documentation for each data file, which can answer many of your questions.