AutoCAD III Advanced
Layouts are pretty much the sheets you use to print the final result of your project. Projects usually have several sheets (plans, elevations, details). You reference your model space through Viewports that act as windows looking inside the model space. Additionally, in layouts you build your Title Block. Title block is the rectangle that has the information project such as name, number, date, revisions and general notes. Usually, the Title Block is blocked to be used across your projects.
Notes & Labels:
That would be the text elements and the arrows you put through out the project to document materials, sheet number and all other notes you would have in your project.
Dimensions are the measurement elements you include in the project. The dimensions section is extensive as Autocad offers a lot of control over it, although can seem daunting in the beginning but once properly understood and implemented you can use it efficiently with no issues.
The final stage in using Autocad, where you print your layouts (sheets) after putting all the different information such as your plan, elevation and details with dimensions and text labels.