Just click "New Name". By default it generates just random names. Alternatively enter a name into "Template Name". Then the generator will create variations of this name.
If you like one of the generated names but want to create more variations of it just click it and it becomes the new template name.
Click the star in front of a name to make it a favorite. Favorite names stay in the list when you reload the page.
Edit the source list
You can enter your own source names into parts.txt. Each line contains a single name split into syllables.