Bespoke round trip

I have found this site very effective for planning straight out & back trips, but I'm struggling to create my own round trip.  I can look at the map and make a route from A-B no problem, but if I want to go A-B-C-D then home,  (in that order to make a round trip) when the site sees that D is closer to home than C it routes me via D before C, or worse takes me on that leg in both directions. .    I see the option to add via points but how do I arrange the route to pass points in the order I need?