Layers - Groups
Layer groups are deprecated since Smart Slider 3.2. We suggest trying the Content mode instead.
You can still use CMD or CTRL to select multiple layers if you're in Canvas mode.
In your layer list you can put your layers into groups, to for example animate them together.
You should just select your layers while pressing the Ctrl (CMD) button, and select the folder icon. Then you will be able to handle the group together to select some settings from the group window.