When I turn on the By me control unit for the first time, or after it has been reset, I am asked to set the Area and Line addresses and the group offset: what does it mean?

According to the KNX architecture, the control unit can manage devices connected different sections of the BUS (each with its own 01801 power supply and a 01845 line coupler that separates it from other sections: each section is identified by an address to be passed to the line coupler during control unit configuration which identifies the Area and Line to which that section belongs. Usable Areas range from n. 01 to 15, and the Line addresses 00 to 15 can be set for each of these). If a By me control unit is not required on a SAI burglar alarm BUS line, set an Area value between 01 and 15, and the Line value between 00 and 15 (e.g., Area 01 and Line 00). If the SAI burglar alarm is used or will be used in the future, the control unit must strictly be initialized with the addresses Area 00 and Line 00, because it is not possible to modify the address of the control unit and so configuration of SAI burglar alarm devices would require resetting the By me control unit and the entire previously configured system. Since a BUS line cannot support more than 128 home automation devices, if for example the control unit was configured to Area 00 Line 00 for the SAI burglar alarm and there were 150 home automation devices to configure, there would need to be at least 2 different BUSes for the home automation devices (for example, the BUS Area 01/Line00 and Area01/Line2) each with its own 01845 line coupler and at least one 01801 power supply.