What does the statement there are 3 kinds of companies those who make things happen those who watch things happen and those who wonder what had happened mean?

It means that that the best company is proactive and is in charge of its own destiny. The second type will just stand by and do nothing to make modifications while better (proactive) companyies pass them by. and the third type the worst of all that did not even have the knowledge to notice that change was coming and therefore did not prepare for it. It was too late - all was lost!