Welcome to the Windows Central forums! We are happy to help you and you can read about pretty much everything connected to Windows in appropriate forum sections.
You can find your own threads under link "Participated" which you can find of the left side of your menu. You can expand your menu by clicking on the button "Your Menu" on the left side of the site header.
Windows is not really a complex operating system, but of course it will take you some time to get used to it if you were Apple user in the past. OneNote is an app you might wanna use with the Surface pen for your notes and stuff like that. If you like to sketch and draw you can use Windows Ink Workspace to get used to it and then switch to your favourite app. I am sure you can read more about it in the Surface Pro section of our forum and you may want to read the Surface Pro 4 review by the Executive Editor Daniel Rubino which you can find
here. I am not a Surface Pro user but I've red quite a few reviews so I can only tell you the basics.
Hope you'll like it here and enjoy your Surface!