New layer is not visible (storyline 360)

Here's the User Guide info about working with layers: Storyline 360: Working with Layers | Articulate - Community

As rachelatkaiser indicated, you need a "show layer" trigger to make a layer visible when previewing or publishing. For example, that trigger could run when the timeline of the slide starts, or when the user clicks an object. 

If you simply want an object to appear on the slide without an interaction, you can simply adjust its starting point on the Timeline (Storyline 360: Working with the Timeline | Articulate - Community ).

Also, be aware that there are various ways to show/hide objects during editing and for previewing/publishing: Can't see the base from a layer? Or is it just dimmed? Is that what you want? Here's how to control base visibility... | Articulate - Community