As to the method of administration . . .
Whereas I'd be interested in what the IAABO and others' states specify, the NFHS book says,
"When administering throw-ins on the frontcourt end line the ball shall be handed to the thrower." And again,
"The Lead shall hand the ball to the thrower when remaining in the frontcourt." And,
"When administering throw-ins on the sideline, a bounce pass is recommended."
Couple of examples for analysis and discussion:
How Could Handing the Ball to the Thrower Be Correct Here?
What Advantage Does Bouncing the Ball to the Thrower Provide Here?