If you're learning Braille, wish to demonstrate your understanding of Braille or not not in a position to purchase a proper Perkins Brailler, then your answer might just be Perky Duck. This is a free simple Braille editor, it basically emulates a Perkins Brailler on a computer.
You can get hold of this software by clicking
[You must be registered and logged in to see this link.]. Follow the on-screen instructions for downloading and installing.
NB: This software is also available for Mac users!