They are Alan Shepard, Gus Grissom, John Glenn, Scott Carpenter, Wally Schirra, Gordon Cooper and Deke Slayton. Memorize those names!
The first to fly, just weeks after Vostok 1, was Alan Shepard. He flew the new Mercury spacecraft on May 5th, using a Redstone booster (a rocket normally used to deliver missiles) on a brief 15 minute sub-orbital flight. He went into space but did not orbit the Earth. He was recovered with his spacecraft in the Atlantic ocean about 300 miles downrange from where he launched.
The Shepard flight was less impressive than Vostok 1, but at least America had put a man in space.
Later that same month, President Kennedy set a goal: that America should endeavor to land a man on the moon by the end of the decade and return him safely to the Earth.