Ugh....

[def90]

Actually the method you listed is the way it is done. They are simply siliconed/glued on. It is likely that the installer didn't do a good job prepping the surfaces. There are plenty of tutorials online and on you tube. Use PL400 for the glue, run a 2x4 over the countertop and clamp up through the drain holes to the 2x4 to clamp it up tight to the counter top while it sets.



If you like you can glue additional blocks of wood to the underside for additional support in holding the sink up to the underside of the counter.