When you open the Layer Slider component, you will see the its interface, which was already introduced in the following article: Introduce the backend.
If you check the admin menu, you can see that there are additional menu items:
In the Transition Builder you can create your own transitions, which can be assigned for the slides, and will appear when the next slide appear. You can learn more about that in the Transition Builder article.
Layer Slider has many built-in skins, which you can also check on the following link : !! These skins' CSS properties can be modified easily in the Skin Editor. A more detailed article is available, which you can check here: Skin Editor.
Of course it is also possible to add your custom CSS code. Imagine that you a text layer on not just one slide. Then you don't need to add the same style definitions for all layers in the layer settings, but you are able to set a class for them, and add the CSS properties for this class in the Custom Style Editor. You can learn more about that in its detailed article: Custom Style Editor.