As @HarishKumar says, in general this is not possible, and will likely be rejected by the journal. Simply put the figure on the next page. There exists a very dirty trick that allows it, but it is a likely reason for rejection. The body of the article has to start by the first section and not by a figure!
It is probably not mentioned in the manual since (1) the class simply never does it and (2) it is the standard, you never have a figure before the body of the document, so the only figures that can appear on the first page are at the bottom of either column, or at the top of the second column (but only the second column).
Ad your comment: There is a way how to put it at the bottom of the first page, but wide bottom figures are discouraged in twocolumn articles. And the trick is a dirty trick that involves manual measurements and seriously manual tweaks. (And if you post an MWE which shows your wide figure at the top of page 2, I can modify it to make it appear at the bottom of page 1.)