How to create a trigger that after adding a record to 1 table will create n number of records in another table?

Question

PostgreSQL

The trigger should work as follows:
1) A record is made to a table (table1) of this type:
SerialNumber: 123456, DeviceCount: N(n ≥ 1);
2) Should work AFTER TRIGGER which in the table (table2) will create N-number of records specified in DeviceCount. Example:
-------------- INSERT Table1 --------------
SerialNumber: 123456, DeviceCount: 3;
---------- Trigger INSERT Table2 --------
SerialNumber: 123456, DeviceNumber: 1;
SerialNumber: 123456, DeviceNumber: 2;
SerialNumber: 123456, DeviceNumber: 3;
------------END---------------------