The budget is announced in the House of Commons by the Minister of Finance, who traditionally wears new shoes while doing so.
This secrecy was felt to be needed for inside information could enable individuals to profit from upcoming government decisions.
Each year, the various departments that make up the Government (for example, Health, Transportation, Foreign Affairs, National Defence, Industry, CRA, etc.)
These documents identify the planned expenditure of each department, linking these proposed expenses to programs, to objectives and ultimately to the priorities of the current ruling Government.
From there, the Cabinet and Prime Minister's Office adjust the budget based on a series of economic, social and political factors.
In reality, decisions are usually made with the primary intent of re-election and so often include advantages for key regions and lobby groups.