To run the program, double click on the EXE. By default a blank grid is set up. TO select an element, click on it to turn it black. Text boxes show the hex pattern by column, and by row (most MCUs will use the column based, as you can pack a single column into a byte).
For Bellfruit MCU and 7x5 matrices in general, do not use the bottom row (some leave this for a cursor, others ignore/blank it entirely)