Connection pins on AD7656

Hi there. Having a bit of a problem here. I have on my board  +5V, -5V and 3.3V and GND Lines. I am working with the AD7656 (Analogue to digital converter. My logical power input Vdrive is connected to the 3.3V and all other power inputs are using +/- 5 and GND. My main problem is the other pins which the datasheet simply state as "when high" or " when =1" eg WR/REF pin, the RANGE pin and STBY pins. If I want them high do I connect to power high ie my +5V or my logic high ie 3.3V or it does not matter.

Please I need this sorted quickly any help will be much appreciated. I have attached the data sheet for viewing