EU INSTITUTIONS
Step 1. Overview and main competencies
The European Parliament (EP) is a unique multinational parliamentary assembly elected directly by the EU citizens (the first elections were held in 1979). The 751 Members of the European Parliament (MEPs) represent over 500 million citizens (after the finalisation of Brexit there will be 705 MEPs). Through the Parliament, European citizens can take part in the EU political process in a number of ways. For instance, they can vote in elections, contact their MEP, petition the European Parliament or launch a citizen’s initiative requesting the European Commission to prepare a legislative proposal.
European Parliament has important legislative, budgetary and supervisory functions. By participating in the so-called Ordinary Legislative Procedure, it is one of the key decisionmakers in the EU as it shares power over the EU budget and legislation with the Council of the European Union. It also plays an important supervising role over other EU institutions and bodes. For example, the Parliament participates in electing the President of the European Commission and the College of European Commission. Please note that unlike a national parliament, the EP does not have the power of direct legislative initiative, which in the case of the European Union lies only with the European Commission.
(Source: http://www.europarl.europa.eu/about-parliament/files/home-page/en-ep-brochure.pdf)
Here is a short paper describing the main competencies of the European Parliament
Now watch this video to learn more about the European Parliament.