Hi Nicolas,
I would check out the following products on Core’s site:
(A similar case than the one in your cart)
(this is needed to allow the 5V Arduino Logic to talk to the 3.3V logic of the E-Ink display)
Power supplies:
I would also take a look at the following link on Arduino’s site for interfacing with SPI: Arduino - SPI
Let me know how you go with your project!
Regards,
Liam.