Sony SPRESENSE Bluetooth LE Add-on board SPRESENSE-BLE-EVK-701 wants to advertise with its own Service, Characteristic

I purchased the SPRESENSE Bluetooth® LE Add-on board SPRESENSE-BLE-EVK-701.

BLE Module Documentation for this add-on board

• MK71251-02 User's Manual
• AT Command Application User's Manual for MK71251-02A
• MK71251-02AAT Command Specification Sheet

As you can see in MK71251-02 User's Manual Chapter 4, "Command Interface", this module has two interfaces: HCI and AT commands.

as described in AT Command Application User's Manual 4.2.1 https://github.com/RohmSemiconductor/Arduino/tree/master/MK71251-02
In the sample shown in , the application mode (Add-on type) is running, and the services and characteristics are unique to Lapis and are fixed (VSSPP, VSA).
Do you mean that in order to add services and characters by yourself with AT commands, the GATT_DB table in the EEPROM needs to be modified from the included Windows application?
Also, in the sample, you can see that the command that starts with "ATS150=" is rewriting the advertisement data of 150 in the S register, but you don't know the specifications of the command.When I rewrite the characteristic value, do I rewrite it with the command that starts with "ATS150="?

In the case of HCI commands, it seems that the OGF and OCF commands can be operated from SPRESENSE to UART, but I didn't know the specifications of the command and the specific steps to advertise and connect.

I would like to use the Bluetooth LE Add-on board SPRESENSE-BLE-EVK-701 on SPRESENSE to advertise in my own Service, Characteristic and rewrite the Value freely, and if you have such an Arduino sample, it would be very helpful.
Thank you for your cooperation.