Something like this is probably what you're looking for:
In your application you don't need the thermostatic mixing valve or the bypass branch from the "return" side feeding it- just a simple loop will do, but you do need a heat exchanger suitable for potable water (almost any size will do for 32' of baseboard) to meet code in most locations. Insert "baseboard" for the labeled "Radiant Panel, Radiators, etc."
The pump on the water heater side of the heat exchanger has to be bronze or stainless or something that won't corrode with oxygenated water, but the circulator on the baseboard side can be a cheaper type.
This diagram may help too:
Instead of the snowmelt manifolds you have baseboard, but you'll need to add a means of filling & pressurizing the heating system side of the heat exchanger. For your application there is no need for the hydraulic seperator & extra pump on the water heater side of the exchanger. You're looking at just one pump on a simple loop, for both side of the heat exchanger.
Basically use the left half of the first diagram for the water heater side, the right half of the second for the baseboard side (but add in a filling valve.)
There's not much pumping head to either loop- a 1/40 HP pump like a Taco 003 or 006 would should be enough. Even 100 equivalent-feet of 3/4" copper is less than 2' of head @ 2 gpm. ) With a 1/25 HP pump it would be over-pumped and noisy. The water heater side is even lower head. If the water heater side is over-pumped and running long duty cycles there is even some risk of flue condensation/damage for a standard water heater, so don't install a 1/25 HP circulator there.