Couldn't have put it better than *see03 myself Basically, you sew on a fabric with holes in that make a grid. Normally aida or evenweave like linen, but you can also sew on plastic. You sew a cross for each block and the colours and symbols match up with numbers in the key. DMC and Anchor are two different brands of thread, and the number is the code for a particular colour, e.g. 310 is DMC black but for anchor black is 403.