To locate EU publications covering policy, try the EU portal EUR-Lex, which contains many full-length documents.
For a searchable record of EU legislation, search this site by the European Parliament.
For a short animated overview of the EU decision-making process, refer here.
And in the world of policy research and think tanks, don’t forget that the main Brussels-focused think tanks include the Centre for European Policy Studies, the European Policy Centre, the Centre for European Reform, and Bruegel.