If you haven’t already done so, create a place for the widgets first. You can add a sidebar to the page. Or if you want the widgets in the center of the page go to:
Appearance>Customize>BuddyPress>Member Front Page> and click Enable default front page for member profiles. This will create another tab labeled Home.
Then go back to the dashboard and go to:
Appearance>Widgets
You can drag widgets from the left side of the page into the sidebars or other sections on the right.