Hi Simone,

This is easy to do.

Open the slider and enable Show Arrows under Elements.

Hi,

This is the CSS code for that:

.et-pb-active-slide .et_pb_slide_description {
-webkit-animation-duration: .7s;
-webkit-animation-delay: .9s;
-webkit-animation-timing-function: ease-in-out;
-webkit-animation-fill-mode: both;
-moz-animation-duration: .7s;
-moz-animation-delay: .9s;
-moz-animation-timing-function: ease-in-out;
-moz-animation-fill-mode: both;
-o-animation-duration: .7s;
-o-animation-delay: .9s;
-o-animation-timing-function: ease-in-out;
-o-animation-fill-mode: both;
-ms-animation-duration: .7s;
-ms-animation-delay: .9s;
-ms-animation-timing-function: ease-in-out;
-ms-animation-fill-mode: both;
animation-duration: .7s;
animation-delay: .9s;
animation-timing-function: ease-in-out;
animation-fill-mode: both;
-webkit-animation-name: fadeBottom;
animation-name: fadeBottom;
}

Place this in Divi > Theme Options > CSS

The CSS code is for different browsers webkit, moz etc. Adjust the number values to change the transition duration.