Most people start off with macros by recording their actions to perform
a particular task - Excel and other Office applications have a built-in
macro recorder to enable you to do this very easily. Once recorded, the
macro can be re-run to repeat the same actions.
To turn this on in Excel, you go to Tools | Macro | Record New Macro,
whereupon you are invited to give the macro a name (don't choose an
Excel keyword), you can specify a keyboard short-cut to run the macro
(e.g. CTRL-ALT-M), and you can specify a few other things once you get
to know what these are.
You can then perform some tasks, like importing a text file and
manipulating the data as you describe above, then press the "stop"
button on the macro recorder. You can view the resultant code in the
Visual Basic Editor (again from Tools | Macro), and edit it or add some
more code. You can re-run the macro from the VBE, or by using the
keyboard short-cut you have set up. You will probably need to change a
few things, such as the name of the file you want to open, otherwise
the macro will just repeat everything you have done over and over
again.
This is a very simple description, but I hope it helps you to get a bit
further with your "manual".
Hope it helps.
Pete