Does a Bill become law once the President has signed a Bill?

It becomes an Act but that does not mean it comes into operation (is promulgated). The last section of the Bill will inform you if it will become law immediately or if it will come into operation later by proclamation of the President. The promulgation of the Act is usually delayed as regulations have first to be drafted. The regulations are drafted by the relevant Department and provide the finer details about how the Act will be implemented. The regulations mostly do not require approval by Parliament although the Department may ask the public to comment on them. Once the regulations are approved by the relevant Minister, the Act may be promulgated. Other matters that can delay the Act coming into operation are the need for training of certain officials, or the need for certain infrastructure to be in place.