Bills are proposed legislation, and must go through a number of stages before becoming law. Federally and provincially, the process is essentially the same.
In the federal system, most bills can be tabled (introduced) in either the House of Commons or the Senate. Bills starting with "C" were first tabled in the House of Commons - for example, Bill C-2 - while "S" denotes a bill which was first tabled in the Senate. There is no Senate at the provincial or territorial level.
Bill numbering re-begins each legislative session, so it is helpful to know approximately when your bill was first tabled.