How to add border around the slider

Border around the slider - Pro version

Go to the Simple slider type's settings, turn on the Expert mode, and you will see a border giving option:

Border around the slider - Free version

Check out your slider's id, and use that to write your own css code into one of the css files of your theme or template, which loads where the slider loads. In my example the slider's id will be 37:

#n2-ss-37{
    border: 3px solid red;
}

Border around the Slides - Pro

Go to the Simple slider type's settings turn on the Expert mode and find the Slide CSS field, where you can enter the CSS code to create a border.