The workflow is simple. You need to do several steps to make your work done.
The initial step is opening file(s) you want to view or edit. You can use the folders tree on the left side of the main window. Once the files are opened, they appear in the file list on the central pane of the window.
The next step is to make the changes to your files. Just select one or more files you want to edit, double click mouse on the selected file(s), and change the data in the appeared dialog.
The last step is to click the "OK" button that automatically processes all your changes. You can see the list of changed files and status messages in the Processing dialog.
To Batch editing just select the files you want to change. Then click button "Edit EXIF/IPTC", change metadata, and click "OK".
Double click a tag in the Properties panel on the right. Select (for enum tags) or enter the desired value in the dialog, and click "OK" to save new metadata.