VBA- Comparsion Chart in on sheet/in a Window/Dialog Box??

Not sure where to begin with my limited VBA skills on this... just need some beginning ideas...

Background:
I have an online program I use and quarterly I log-in and view a list they post of "text changes to the content"

I then have a SharePoint file that I open and compare the contents of a portion of that SharePoint file to the online "changes" page and see if any text content overlaps .. if content is found that overlaps it gets sent downstream for evaulation of changes.

Currently this "change review" is manual...

Is it possible to go about opening excel or word.. and having a icon on the ribbon that would be pushed and it would run VBA code to do this change review. The code would end up spitting an end result out that looks like the results of the "Control F" usage. It would have some sort of 2 column list .. on one side would state "matched change content" and the other would state "impacted document" .. it would need to allow for partial matches as there are possible differences in entry and several items have 2-3 words with-in each entry and the other document may not have captured every word ...

Basically:
is it possible/how do you run VBA code from icon on ribbon? How would the code "always" be in excel/word so everytime I open the application itself the icon is there.. ??

is it possible to create code telling the word file to open internet explorer and to go to a specific web addy? ... and then entering the needed password?

Is it possible to have a dialog box pop up at the end with the results ... or would it be much easier from a usage/code writing aspect to just have the results populate on a new workbook sheet?

Thanks as always!

Great step in right direction ...thanks!... I get to step 4 of the provided link ... but my macro/add-in does not show up in the list... all that I see in the list is the word "<Separator>" once I choose "Macros" in the "Choose commands from:" pull down menu ??