For [TO H0D H2 D324 K1] means to send data to module with Start address H0D by send data from D324 to Analog Output channel 2
TO > TO instructions
H0D > Module No. (Start Address)
H2 > Destination Buffer Data (H2 = Analog Output Channel 2)
D234 > Source Data
K1 > for 1 word
I have highlight H1 to H3 on attached picture