And what do you do if a large corporation uses your invention anyway, and doesn't tell anyone they're doing so? Firstly, you have to find out they've infringed

And what do you do if a large corporation uses your invention anyway, and doesn't tell anyone they're doing so? Firstly, you have to find out they've infringed. Secondly, you have to sue for protection. How will you accomplish either of those steps, let alone both?