It's quite an old device!
Basically, look at the pins this way:
BUSY = a conversion is in progress so don't read the outputs yet.
RD = enables the output drivers, turn them off until needed if the outputs share a bus with other devices. Usually, the pin is called something like 'output enable'.
CLOCK = moves to the next successive step in the conversion process. You need to toggle this bit as many times as there are bits in the result you want.
WR = starts the conversion process, think of it as a 'start conversion' signal.
Hope that helps!
Brian.