how to generate multi-channel voltage at same time

I am a new Labwindows user,I need to use the onboard clock to update 4 voltage arrays in 4  different AO channels .After I Write all of my 4 voltage arrays into the buffer ,I find it can only generate one by one, more than starting at same time .Should I use two-dimensional array to save the 4 voltage arrays ,which will be write to the buffer by using this two-dimensional array rather then four one-dimensional arrays?Thank you for your help.