How to calculate height difference using Sentinel 1 products

Hello everyone,
I have to calculate height difference of a coastal area subjected to a strong event of marine erosion in the last month.
My idea is to use an image acquired before the event, obtain the height, then, using an image acquired immediately after, compare the two heights and calculate the delta. It is possible? There is somewhere a tutorial that summarize these steps? What’s the error is associated with these measures?
Thank you very much