The hardest thing about new versions with significant changes is figuring out how to find the commands you have been using in the new version.
This post is just a very general overview of some of the main areas and where you can find these things in version 4 versus where they are in version 3.
The main thing to remember is that the options in version 4 are context sensitive. This means that when you click on an icon, options for that function will be displayed.
Compare the images from version 3 and 4 above. The numbers beside the icons show where that function is in the other version. You can click the images to display a larger version.
I hope this is helpful to you. Many more posts and videos will be available soon.