Theres not much science to root a purple mombin, these specie is one of the
Easiest ones,here they use them to hold the fences in the fields,just cut them
Stick them in the ground and soon they start to send new shoots ,in a year theres a little tree, all you need is semi hard or hard wood, put half inside the ground or pot, with good drainage and 50% shade maybe you can bag it or look at the topic here in the forum "how thanks to Pepsi I have root many cuttings" thats very helpfull, one thing is you need to hurry I see you are in california and to promote rooting you need temps above 23 celsius,so take advantage of your summer now!