Braces AND a palate expander?

hi everyone! so i went to my new orthodontist and she told me i need a palate expander and a full set of braces. however, i swear she had absolutely no idea what she was doing. so, my mom made an appointment with my original orthodonist and he said i needed the same thing the last time i visited him which was six months ago. My new orthodonitist also tol dme i have a terrible overbite and need braces AND a retainer! i have already had a palate expander and my mouth shifted back! he told me that during my next appointment (next friday) he was going to put in spacers and take moldings. what i am wondering is, is he able to put the braces on the saem time i have the palate expander? or do i need the expander first, finish that, and then get braces? im getting a permanant one that has to be turned everynight. thanks so much everyone!