Could someone tell me if these steps are right for a IAT hook?

[NecroPotence]

I already have the IAT hook function ( Tested it in vc++ and it worked =) ) but I need to use GetModuleHandle(0) so I can get the handle of the client, these are the steps I figured out:

CreateProcess(with the client)
SendMessage(getmessage)
SetWindowsHookEx(msg = ?, with client)
IAT hook
unhook


could someone please tell me if this is the right way? Thanks.