Once the initial setup is complete, there are only two more steps before you can start browsing your pictures:
Configure your library and advanced settings according to your individual preferences.
Choose whether you want to index your originals directly, leaving all file and folder names unchanged, or use the optional import feature, which automatically removes duplicates, gives files a unique name, and sorts them by year and month.
If you want to use folders that already exist on your computer, make sure you configured them as originals respectively import folders during setup.
To add new pictures, you can either copy them to the originals or import folder or upload them using a browser, which will automatically import them once uploaded.
Then start indexing or importing, depending on which strategy you have chosen.