Hey Maxglo,

This slider is using custom navigation areas. You can choose skins from the available list in the Slider Settings -> Appearance tab. 

You can also build your own navigation area. However, please note that at the moment there is no built-in option in the plugin to relocate or edit the navigation areas, you would need to do some coding to achieve it. Please note that it requires custom coding and web development experience so it is not recommended for unexperienced users. 

Alternatively, you can make a new skin or modify one, but it also needs some CSS knowledge.

You can approach this two ways. You can either edit the image file that contains the arrows. It was created with a "CSS sprites" method, meaning that only certain parts of the image is being showed.
As long as you do not change the arrows' sizes drastically and leave it in the correct position in the image file, you can freely change it. This method does not require CSS editing.

Or you can edit the skin.css file. The classes you are looking for are .ls-nav-prev, .ls-nav-next