There is a flow diagram on page 9 here.
http://www.watergeneral.com/support/pdf/RD100.pdf
Out of the first 3 filters, it goes to the high pressure, in side, of the ASV then out to the ro membrane high pressure side.
But if you bought a ro filter system, already together, except for the water in and ro water out to your tank, also drain connection, Then normaly the ASV is already connected. Follow all the lines, you should see the ASV under one of the cigar shaped filters on top of the unit.