The last couple I've done came with a small tube of sealant that
looked just like normal flexible tub caulk. I let it set up a few
hours before I completed the plumbing, so it wouldn't shift around.
The amount they sent me wasn't much, so I used tub caulk to make a
smooth bead around the edge. The weight of the sink was more than
sufficient to keep it in place. Much nicer looking than the ones with
an aluminum rim, IMHO.