ArduinoBLE library in custom PCB

I have a custom PCB with Atmega328. I'm looking for a BLE module that allows me to use the ArduinoBLE library to create services and characteristics but I don't know how to do it.
On the ArduinoBLE library page it says:
"This library supports all the Arduino boards that have the hardware enabled for BLE and Bluetooth 4.0 and above; these include Nano 33 BLE, Arduino NANO 33 IoT, Uno WiFi Rev 2, MKR WiFi 1010."
What does "have the hardware enabled for BLE" means?
I just want to find a way of creating characteristics and services from Arduino IDE in my current code.

Nano BLE has BLE in the MCU. All other listed boards use the on-board Nina module (ESP32) with the Arduino nina-fw for the BLE

My question is: how can I use the library ArduinoBLE in my custom PCB? Do I need a specific BLE module... BLE is a new field for me so I have a lot of doubts

you would have to use an esp32 with the nina-fw. but it would be much simpler to use only the esp32 MCU