So you weren't actually interested in all that discussion about the matrix connections?!
You could have save a lot of people a lot of time by making that clear earlier!

Well, you just consider the LEDs as a matrix of pixels; eg, for a 5x7 matrix:

  . . . . . 
  . . . . . 
  . . . . . 
  . . . . . 
  . . . . . 
  . . . . . 
  . . . . . 

So you just have to decide which pixels to activate to display your required character; eg,

  * . . . *  *********  * . . . .  * . . . .  . * * * . 
  * . . . *  * . . . .  * . . . .  * . . . .  * . . . * 
  * . . . *  * . . . .  * . . . .  * . . . .  * . . . * 
  * * * * *  * * * * .  * . . . .  * . . . .  * . . . * 
  * . . . *  * . . . .  * . . . .  * . . . .  * . . . * 
  * . . . *  * . . . .  * . . . .  * . . . .  * . . . * 
  * . . . *  * * * * *  * * * * *  * * * * *  . * * * . 

Where '.' represents an inactive pixel; '*' represents an active pixel.

You could use a lookup table to determine which pixels to activate for a given character.

You can design your own font on graph paper, or copy from an LCD datasheet, or search for utilities to do it automatically...