Dave the questions you ask are training-related and can be done very easily. You can book in one on one training via the website here https://plusspec.com/online-training-2/
to extend the roof over the post simply move the edge to the post, right-click the face and select +roof. Note you can create a roof anywhere by simply right-clicking a face. Tip if you would like to create a roof with multiple overhangs simply choose your eave overhang to be zero right-click the face and create a roof from the face
You can create the plans for the house you have added easily, by simply following the tutorials in the question mark at the top of each tool. OR Check out our Youtube channel
I suggest checking out the tutorials at the top of each tool as a list of video tutorials will come up and you can get to what you need to know very quickly at any time of the day month or year.
Dave the wall type you are trying to create is called a Wainscott wall you can choose it from the drop-down in the wall tool and you can set the height of the brickwork split height.
Hey, David Andrew created a tutorial on how to do the roof. Even though this roof can be created parametrically as per this video https://youtu.be/VC_5ISfWDyI remember you are inside of Sketchup so If PlusSpec or PlusDesignBuild can’t do it Sketchup will. Sure it may be a little slower but it is quicker than waiting for a response when we are on holidays.