$5mill is a long way from becoming a majority shareholder in multiple $Billion Dollar companies - you just start buying stocks thru an online or regular broker - there are legal and regulatory issues once you get near 5% ownership of a public corporation

I'm just getting into business, and I have a lot of interest in a few specific companies. I'd like to eventually become a major shareholder in these companies. Whats the best way to go about buying shares of huge corporation. I'm talking about companies with a 20 Billion USD market cap. I'm currently worth about $5 million in total from just working hard for a few years but I'd like to now start getting into business on my own. Suggestion's on how to learn how to do this?