I believe you can use any remaining available IO pins for those pins.
Just specify the pins you are using in the line which declares the E-Ink class instance.
If you look at the examples that come with the library, you can see that those pins are defined in the sketch.
Note, for the SPI pins in the sketch, you should use the SPI pin names (e.g. MISO, MOSI, SCK & SS). The digital pins listed above are for reference as to which physical pin to connect the wires to.
Also you can really use any pin you want for the CS/SS pin, as when the board is in master mode, this is simply an IO pin for signal activating the connected slave device/peripheral.