The sequence of events are the following:

1. Define you VLANs.
2. Define your Flex Profiles.
3. Define your Policies.
4. Define your WLANs.
5. Define your Tags.
   1. Assign the policy Tag.
   2. Assign the site Tag.
   3. Assign the AP Policy/Tags.

There are 3 types of NATs on a FTD:

1. NAT Rules Before. This is equivalent to Twice NAT (section 1) on classic ASA.
2. Auto NAT Rules. Section 2 on classic ASA
3. NAT Rules After. This is equivalent to Twice NAT (section 3) on classic ASA.

https://www.cisco.com/c/en/us/support/docs/security/firepower-management-center/212702-configure-and-verify-nat-on-ftd.html

Setting up simple eBGP on a Cisco FTD

Start by going to Devices -> Device Management -> The FTD in question and hit edit -> Then Routing Set the AS and Router ID.