There are two ways to ask Spotless to tidy your files, you can either drag & drop files to the Spotless drop target, or configure an Automation job.
An Automation job asks Spotless to process all the files found in a specified folder at regular intervals by defining a schedule. You can have the Automation job run a specific task or ask you when it starts to run, although usually you will run a specific Task. This allows you to configure Spotless to regularly tidy the files in a given folder so clutter never builds up.
When you first run Spotless you will be asked if you would like to create a default task and Automation jobs to tidy your Desktop and Downloads folders. These can be configured manually at any time, but provide a quick way to get started.