Please provide links to learn GLS (gate level simulation)

How to learn GLS (gate level simulation)
please provide any web link or videos links …etc?

In reply to Subbi Reddy:

This is an extremely broad question. You might want to start here.

A side note: as an unfortunate coincidence, many links to both Siemens and DVCon articles are broken at the moment due to changes in website hosting issues. So keep trying.