in very top right of screen, on banner is an icon that is a circle, broken on top with a dot in middle of break. hit it! >>Joel Weisberg (or your name here)>>Account Settings.
Look on far left of resulting popup at the “Details” column which has a left arrow next to it.
Hit the left arrow to open up the “settings” column and scroll ‘way down to, and select “privacy.”
Then hit <cntrl>screenlock and you can select from a menu of “lock screen after blank for
<? minutes>.
–Joel. (Yes what a pain! This was really hard to figure out because it is so buried.)