What is the most logical next event?

How to install a bay window
Remove enough siding from the wall around the rough opening to reveal the building wrap underneath.
Uninstall any existing window from the wall.
Make sure the studs and header around the rough opening are safe and can support the bay window.

Possible answers:
A). Use a hammer and nails to roughen any edges of the window and the back of the frame so it is even. Replace any hinges facing the bay window.
B). Prepare the sill for the bay window as directed by the window's manufacturer, such as by adding a drain mat. Drill evenly spaced pilot holes around the bay window's inside perimeter.
C). Measure the surface of the building wrap. The texture of the roll cloth will determine how you proceed.
D). If you are installing both the front and back panel, secure these hinges in the studs with screws to keep all the panels from falling over during installation. Loosen this bracket and some of the backing boards by pressing them inwards.
B).