If you use the security assist wizard rather than creating the login manually, it will create the access rule for you. along with the user update, login and logout page
If you want to create the login manually:
on the last page of the security assist authenticate user behavior, it is storing the id column value to a session variable named "id"
if you open the bindings panel, and expand the session collection, you should see a binding there named "id".
Open the security assist Access rules Manager (Modify -> Security Assist -> Access Rules Manager) and create a new access rule.
Click the allow radio button
For the value, click the lightning bolt icon and select the id session variable binding
Set the criteria to "<>"
and leave the compare to value blank
this basically says:
Allow if the id session is not empty
only if the user is logged in will the id session variable not be empty