I don't have a Glass BSDF I am new to blender and am trying to make a gemstone. I already have it modeled and am on to texturing but the tutorial I found uses a glass bsdf but I don't have one in my add node selection. I tried googleing it but all I found were more tutorials. Do I need to turn something on or download it?
Thanks in advance.
You are in the wrong editor window (texture editor)

Use the Shader editor.