Insert and delete column with macro

I have master data that need to be edit first, it contain many unused columns but not merger and i want to delete those columns after that i need to insert a few column too with formula inserted.

before: please delete column C
a b c d
1 one two three
2

after: please insert 1 column after column A and 1 column after column D
a b c d e
1 one NEW1 two three NEW2
2

and the last one please do this using macro on different file excel so will not change the master one, please anyone help me, i dont really know about coding. Thanks in advance
i ever asked in it e few forum but still not get the answer.