my response is who decided that air was a good source to live off of and how to collect it into a breathing aparateus?
That's a better question than you think it is, Voice. For the first 1500 million years of life on Earth, air like ours today would have been pretty much deadly poison. What critters there were back then were apparently all one-celled and made their living by doing chemical reactions on hydrogen sulfide, nitrate ions, dissolved iron, and whatnot. But about 2200 million years ago, the ones that used sunlight to split water and make oxygen got the upper hand, and free oxygen started showing up in the atmosphere. A lot of bacteria died out - the oxygen killed them.
But some that had mutated proteins to let them use oxygen found a gold mine - you can get a great deal of energy by reacting things like sugars with oxygen. The early organisms that did this didn't need gills, as they were tiny and single-celled. They just absorbed oxygen and released carbon dioxide through their cell membranes. Maybe 1600 million years later were the first bunches of cells living as a unit, where there was an advantage to having one part of their bodies used for oxygen/CO2, while another part did something else. In other words, gills didn't come about all at once.