Please expand your question. I don't understand what you are asking so I can only offer some general advice for now:
* The ADS868x is able to interface with the Pi as you have already suggested using SPI and a handful of GPIO lines.
* It is 3V3 logic so you will not need any level shift.
* The SPI bus on the Zero is on pins 19 (SPI_MOSI), 21 (SPI_MISO), 23 (SPI_SCK), and there are chip selects on pin 24 (SPI_CE0_N) & 26 (SPI_CE1_N) you will only need the one chip select line (your choise which), likewise it is your choise which GPIO lines to use.
* Section 7.4.1.x of the ADS868x datasheet shows the suggested interconnetion.
It also suggests that some issolation barrier may be used if you want to seporate conducted noise from the digital syetm (the Pi) and Analogue side (including the DAC).
* At bare minimum I would place series termination resistors on all of the control lines and the spi bus to reduce reflections
(but unless you are going down the route of controlled impeadance tracks between your Pi and the DAC to get correct matching, a simple 33R anywhere on each net will probably work fine).
* DACs always work best with a clean power supply. A seporate power rail and issolation of signals from the Pi will make a differance to the output noise - but depending on your application this may not be needed.
* Likewise noise can be reduced by carefull PCB layout; think about signal coupling and clean signal path