Afraid to say its a learning process it's different for everyone.a few basics though raw veggies,onions,greasy food,salad stuff generally can be bad so treat with caution.veggies well cooked or blended in soup are generally ok.alcohol wise beer,lager try it in the house in case of disaster.i,m fine with fish,beef,pork,potatoes,carrots,peas.i,m try to reintroduce salads and coleslaws back into my diet I miss them.
Cheers all the best
P.s melon is a huge trigger food for crohns 1slice marked my soul