User Identity Policy on FortiOS v5.4.1

Hello,

I am hoping someone can help me with my query.

I currently have a couple of FortiGate 100D devices, running firmware version 5.0.  With these devices I have two-factor authentication setup for my users.  I have a "user identity" policy in place and an "authentication rule" setup within the user identity policy.  This all works perfectly, as expected.

Now for my dilemma...

I am replacing the 100D devices with new FortiGate 300D device, running firmware version 5.4.1

I now want to configure two-factor authentication, in the same way as I have on my old 100D devices.  However, I cannot seem to find the options for a user identity/authentication rule.

I have read the FortiOS Handbook and it is still unclear as to what I should do.

Could someone please help.

Thanks in advance.