What actually is the European Union?

The European Union (EU) is a unique international organisation. Its budget is set by and paid for by all Member States. The budget is mostly focused on spending to create growth and jobs and reducing the economic gaps between the different regions of the EU.
The European Parliament
The Parliament is directly elected by people from across Europe. It can amend and have final say on proposals from the European Commission.
The European Commission
The Commission is the civil service of the EU and is led by Commissioners. They are nominated by the Governments of the Member States.
The European Council
The Council is made up of the heads of state from the Member States, the Prime Minister of the UK is a member for example. There are also meetings of Ministers from the Member States such as the finance ministers or agriculture ministers in their respective Council of Ministers.
How does it work in practice?
The heads of state (The Council) set the direction and agenda for the EU. The Commission then proposes actions and legislation to carry out the direction. The Parliament and the relevant Council of Ministers then have to approve or amend what the Commission suggests. The commission implement the decisions taken.
How can people get involved in it all?
MEPs are directly elected and accountable to the public. The Parliament can vote down proposals suggested by the Commission. The Council is made up of the Ministers and Prime Ministers and Presidents of the Member States so there’s also the usual national route politically.