Digital Terrain Model (DTM) Generation

Does anyone have a good process for generating a Digital Terrain Model (DTM) in Snap?
Can this be done on a single Sentinel-1 scene, or does it have to be on an unwrapped product?

Please have a look here:

On other data
Interferometry Tutorial with Radarsat-2

Do you know if a DEM can be made with just one Sentinel-1 scene? Or does it have to be 2? I suppose if I had a pair of scenes that were very close in time, it would be ok.

Creating a DEM from radar interferometry requires two images of different dates, but not any data can be combined. The crucial step is to find a pair with suitable characteristics (same relative orbit, short temporal and large perpendicular baselines).
Please have a look at the article I listed above which gives a good introduction.

Thanks, I’ll look at those. Is there any singular product coming from Sentinel that can be used to generate a DEM? Or do all end products require two images?

any DEM requires at least two images, this applies for both optical and radar data.