@AdamB, Welcome to the forum!
Your setup is perfectly doable without CAPsMAN. For a single hAP be lite, you can configure the SSIDs and map them to VLANs directly using the local WiFi configuration. CAPsMAN mainly becomes useful once you want to manage multiple APs centrally.
The newer WiFi devices also use the /interface/wifi stack, not the older /caps-man menu, which is why some of the guides you find won't match your device.
When it comes to VLANs, Mikrotik RouterOS handles them in a somewhat unusual way through its bridge and VLAN-filtering model, so it might be worth reading up a bit before diving into more advanced VLAN setups.
A few good starting points:
- Beginners journey into VLANs
- Using RouterOS to VLAN your network
- Tutorial: Home VLAN configuration (RB5009, cAP ACs, multiple SSIDs)
I'd start with a minimal working config, keep at least one physical port outside the VLAN-filtered bridge as an emergency management port, and add one VLAN/SSID at a time.