Regarding modeling, everyone has different habits and uses different methods and steps. If you can't find the direction, I suggest you look for more tutorials on the Internet to see how others use them and sum up the most suitable ones. There are many tutorials on the Internet, which can generally be found in The Age of Mars in Hu Yi. Com and so on.

For extrusion, it is generally a point, line and surface operation. First, select the desired point, line or face, and then use the stretch command, which is the operating handle where stretching occurs. By operating the handle, you can move, rotate and scale the newly generated points, lines and faces. Click the small blue circle on the outermost side of the joystick to change the reference system of the joystick to the world coordinate system. I suggest you read more tutorials, especially video tutorials, which will be more intuitive.

I hope I can help you!