Man on third. Batter bunts. Run scores. Batter is safe at first. How is this scored.

Many possibilities, a little more description would help...

Was the ball missplayed? How many outs? Did they make a play on the runner at home and he was safe? Was it simply a bunt base hit?

If the ball was miss-played and < 2 outs
1.) the run would've scored but the runner would've been out at first with ordinary effort, then credit sac and reached on E, rbi
2.) the runner at home would've been out with ordinary effort, FC to hitter and no rbi, runner scores on E
3.) neither runner would've been put out with ordinary effort, hit & rbi

If the ball was miss-played and 2 outs
1.) the run would've scored but the runner would've been out at first with ordinary effort, then reached on E, no rbi
2.) the runner at home would've been out with ordinary effort, FC no rbi, runner scores on E
3.) neither runner would've been put out with ordinary effort, hit & rbi

If fielded cleanly with no opportunity to put runner or batter out, hit and rbi (regardless of number of outs).

If fielded cleanly and attempt made on runner at home, who is safe, you must decided what would've happened if they'd tried to get the batter out. If he would've been out with ordinary effort, score sacrifice and RBI (if < 2 outs), or score fielder's choice and RBI (if 2 outs). If he would've been safe with ordinary effort, score single and RBI.

Thanks you answered my question. You need evaluate the play and some situations can be a judgement call. Is this correct?

Absolutely.

If the ball is missplayed, ask was that "ordinary effort" for the level of play. In MLB it means one thing. In 8U coach pitch, its quite another.

Score errors\hits based on that. Reaching on a bunt can be a hit\sacrifice\FC or error depending on the situation, number of outs, etc.

Baseball is so much more interesting to watch when you have a scorebook in your lap...