The Contents Panel shows all the topics in the project, rather like
Project Manager in older versions of Adobe RoboHelp.
With a topic open, the Right Panel shows the Properties and Styles.
Properties reveals Element and Topic information.
Styles shows the styles in the CSS selected.
Here you will the assets folder along with whatever structure you create for topics. If you look in File Explorer, you well see the project structure differs from earlier versions.
If you look at the project in File Explorer, you will see the root folder contains the rhpj file that opens the project.
Your files are in the Contents folder where you will also find the Assets folder. All the other folders are for the Adobe RoboHelp 2019 internal files.
You will also see JSON files in your project. These are cache files used by Adobe RoboHelp 2019. Don't touch!
The Assets folder is new. The idea is to keep your images, CSS and suchlike separate from your topics with their own organizational structure.
Right click any folder or file and you will see the various options available, similar to previous versions.
When you upgrade, all the image,
media and CSS files will be moved from their existing locations into an
Assets folder. The folder structure of your project will be retained for
folders containing such files.
For example, if you had all your images in a folder named Images and your
media files in a folder named Media, in Adobe RoboHelp 2019
you will see Assets > Images and Assets > Media.
When you open a topic that is in the Contents Panel, the content appears alongside with its Properties in the Right Panel. See Working on Topics
There's a great new feature
here, Import Folder. Click that and you can then browse to any drive you
can see and select a whole folder of, for example, images or you can browse
and select multiple images and add them in one go.