Resumption of Play Procedure

[ChuckS]

Rookie here, who is beginning to get a handle on the basics. Time to tackle the resumption of play procedure. I have read the NFHS rule many times.

Team A calls time out before their backcourt throw-in after an OOB call. I am administering the throw-in, and as the 2nd horn sounds, Team B is on the court, ready to play. Team A remains in their huddle.

I assume I can place the ball on the floor and start the 5-second count, "x" seconds after the final horn.

The rule seems to indicate that x=0. But I have a feeling that properly managing the game will allow for x to be greater than 0.

What guidelines/judgement can I use to determine "x". (sorry, I'm an engineer!)