Operating AD5780 EVAL Board Via MicroController

OK, so thanks in advance because I am new here. I am reading the AD57XX drivers here  https://wiki.analog.com/resources/tools-software/uc-drivers/renesas/ad5780 and am struggling to understand how to get the device working and understanding it properly. I am using code here https://github.com/maxgerhardt/arduino-ad57xx-driver/blob/master/src/main.cpp in order to test the DAC. I have several questions about the drivers and operation in general. I will itemize them if that is ok

  1. Where in the drivers am I performing Slave Select and where am I determining Clock Speed? I have looked through the C in the drivers library, and it seems that each command, whether reading or writing selects the Slave/Master each time? I see no reference to which pins on my microcontroller it is reference though so I do not know if any of this is right.
  2. Why do I need to be reading in the Control Register or anything from the DAC at all? Why does this matter? All I want is to output a voltage
  3. How do I perform the right conversion to a voltage that I want? The command " AD57XX_SetDacValue() " takes a long, but I do not understand how that relates to a float value of voltage. Say I want 2.35 Volts, or a Sine Function from -2 to 2 Volts, how do I do this conversion?
  4. I don't know how to debug the system in general. When I run the example code, which is supposed to output a triangle wave function, I get a sin function. Is this just background noise that the DAC outputs. I don't know how to tweak parameters or understand it. If the photo is low resolution, from peak to anti peak, the wave function is only about 300 mV.

Thanks in advance for all the help.