Ive taken mine apart a lot.
I'd start with the front seats, 4 bolts each, 17mm i believe, 3 connectors each I believe. Unhook battery for airbag stuff.
The console trim, lever in D, ebrake on. park brake up. small shift knob off. Pull up cover with your hands.
Three wire connectors, two seat heaters and the power button.
I think 4 screws on both sides of console, easily accessed after front seat removal. One or two vertical screws inside bottom of console. There might be two screws behind the console pull out drink holder tray for the back seat passengers. MAybe two screws under the shift cover panel. You might not need to remove the center lower tray or the console. Im not sure for carpet removal. By this point you'll know one way or the other.
All the sill scuff plates have push connectors, use a plastic pry tool. The lower cowl covers by drivers and pass feet have screw knobs. They come right off.
Center pillar covers need to come to. The pull right off.
At the rear, remove carpet pad, remove plastic hinged cover piece that covers tailgate hinge area with 4 or 5 screws, then it will just pry off, pull up on it.
the lower rear trim pieces in the rear, the ones that cover rear AC and subwoofer have black plastic caps. 3 i think. two in the corner at the bottom, one forward of the jack mounting bracket. Four seatbelt bolt anchor points, 14mm.
Also the net clips/ looks like clothes hanger hook/ twist out with a screw underneath. The are chest high in the piece closest to rear tailgate.
The rest are just push clips/buttons on the trim and they will pull out, might take some effort
power socket wire connector drivers side. Plastic covers on anchor points on the floor( a lot) need a small torx bit. remove those.
Rear carpet will lift off now. It's velcro ed to center carpet section. it will pull out around the anchor point steel/striker cups in the center of the rear floor.
Middle seat rows I can't help with.
It helps to have a new bag of trim clips. I use these, they are better than the white ones. Also I have used a glue gun to repair certain sections that break or get deformed during removal.
Amazon.com: 25 Toyota Trim Panel Retainer Clips 90467-10188 Sienna: Automotive