Paul Ryan and kids rehearse for their big moment. (Bonnie Jo Mount/Washington Post)

Paul Ryan took the podium at the Tampa Bay Times Forum. He looked out at the sea of reporters and photographers. And then he leaned into the microphone and began to speak, as those below waited with bated breath to hear what he would tell them.

"1, 2, 3, 4, 5, 6, 7, 8," Ryan said. "How about 9, 10?"

The GOP vice-presidential hopeful went on the stage at the Tampa convention shortly after 3 p.m. for a walk-through of the venue where in a few hours, he will deliver the biggest speech of his life.

He was accompanied by his wife, Janna; his older brother, Tobin; and his three young children, 10-year-old Liza, 8-year-old Charlie and 7-year-old Sam.

Ryan typically delivers his speeches with a hand-held microphone and notes that he only occasionally glances at. His debut tonight on the convention stage will pose new logistical challenges, including a teleprompter.

After the test, Ryan's daughter, Liza, approached the podium and appeared to try to test out the microphone.

"It's not on," Ryan told her, before the test-run wrapped up and the entourage disappeared backstage.