It's not actually a DEM, but a DSM file or DTM file I want to import. The DEM option is available. Thanks for the help. I don't have the point cloud module, but it looks like it would work. In the meantime, I know smart people who help me create the *.tin, so until I figure this out, that's what I'll do.
If you would like to give it a try, follow this link:
https://lidarportal.dnr.wa.gov/#47.51508:-120.45677:16