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.
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.