P5 64x32 LED Matrix + ATMega2560 missing D, E

Hi Everybody,

I want to ask for help on the following topic.
I have a P5 64x32 LED Matrix and I want to connect three of them to display a number in 3 digits.
I would like to control this with an ATMega2560, which would be supplemented with a W5100 Ethernet shield so that the value can be changed via Blynk.
It already worked with ESP with a 32x16 display, but:

Maybe someone would have an idea, an example program?

Thank you for your help.