The way I did it was, I first made blackened chicken breast (see below), and then brown the sausage, to the point where I think if I cook it longer it'll be too dry. I then cooked the vegetables, add stock, and boiled for 30 minutes before adding rice.
Blackened chicken breast: chicken breast seasoned with salt and pepper, dipped in spice butter (butter cooked with cajun spice), and then seared in a hot cast iron skillet.
Honestly I never had cajun jambalaya in a restaurant before, so I don't think how it's supposed to look like. Does mine have enough "brown" to be considered proper color?