How can I insert identity manually?
Yes you can set identity fields manually executing
SET IDENTITY_INSERT masterTbl ON
then insert your data
INSERT INTO masterTbl (id, name) VALUES (1, 'MNO')
......
and remember to call
SET IDENTITY_INSERT masterTbl OFF
to reenable the correct functionality
SET IDENTITY_INSERT masterTbl ON
https://docs.microsoft.com/en-us/sql/t-sql/statements/set-identity-insert-transact-sql?view=sql-server-2017
In it's simplest form, you need to temporarily allow the insertion of identity values
SET IDENTITY_INSERT masterTbl ON
INSERT INTO masterTbl (id, name) VALUES (1, 'MNO')
SET IDENTITY_INSERT masterTbl OFF