edited to add: the keys needed to type a dot are esc-.-esc, but I still haven't found the documentation to that effect. Maybe I will write a program to record my long and frustrating travels through the Wolfram documentation.
Here is how not to find the answer: Start by typing esc-d-o-t; give up on that. Now go to the front page of the Documentation Center. Search "Dot". After realizing you have made another mistake, go back to the front page of the Documentation Center. Press random links until you find yourself on "Wolfram Language Syntax". Then you see "Mathematics & Operators", in orange, and under that you see a "+' and a "*" but not dot. Another dead end, or is it, because things in orange might be hyperlink, or they might not, and you won't know unless you take a gamble and try. Click it. Nothing. Lost the gamble. 20 more minutes killed, no dot, and no math done. When I was a kid, we would just push the #2 pencil into a piece of paper, and the dot would happen.
My little latex paper I'm writing has an index on the last page of all mathematical symbols used in the paper, scan the index, see a symbol, the index tells you what page the symbol is defined on, with a hyperlink to the definition....