What defines how to, "constrain everything properly" depends on what you're after results wise and what you want the joint to capture physics wise.
That being said, the most basic method for doing it is to use a beam element defined by a curve, weighted-links to "connect" the beam element the relevant components, and then apply a temperature load.
For the temperature load, you'll use structural temperature load (see image) and apply it along the curve you used to define your beam element. You'll need to play around with the total temperature change to capture the proper pre-load.
