Tori is correct that SketchUp doesn’t come with a .glb or .gltf export option, but there is this free extension that does seem to still work:
https://extensions.sketchup.com/extension/052071e5-6c19-4f02-a7e8-fcfcc28a2fd8/gl-tf-export
It hasn’t been verified with SketchUp later than 2016, but seems to work ok in 2020. You find the export option in Extensions/Khronos glTF.
SimLab also do an exporter. The extension is free, but I believe it uses a paid for license to do the actual export: