i just installed Bulletproof Security plugin and are not

i just installed Bulletproof Security plugin and are not entirely sure what is required in a Multisite set up. The instructions advice not to network activate but what I am wondering is if this needs to be activated and set up on each sub site? I imaging the parent site would be sufficient as there can only be 1 .htaccess lockdown achieved.

Would appreciate any feedback on this.
thankyou