I am using blender for the very first time today, and I'm trying to make my stairs white and have a glow around the whole staircase. It looks just the way I want in the material preview, but how do I make it look the same in the render preview? What is the problem that caused it to look so drastically different? Thank you in advance.
Material preview uses a hidden HDRI image for a source of lighting and reflections. If you want to add one yourself, go to the Shader Editor, and change the box in the middle left from "object" to "world". Then add an Environment Texture
(Add > Texture > Environment Texture) to the graph (not an image texture) and select an HDRI for your image. The ones that come with Blender are in the Blender Folder at
.../2.93/datafiles/studiologhts/world (.exr files). You can also find them online for free in many places - one of the most popular is HDRI Haven (https://hdrihaven.com/hdris/)