Definition of bat and reach first safely

[youngump]

So I was trying to understand rule 4 better last night as well. In rule 4 it says that an unreported substitute who bats and reaches first safely is out if timely appealed. But what does bat and reach first mean here? Does it mean they have to hit the ball, or does getting hit or walked count?
If I'm the alert slow pitch DC, is the correct way to leverage this rule that when an unreported substitute comes in I immediately intentionally walk him and then appeal? If I'm the semi-alert OC who forgot to report the sub and realize what's going on when the intentional walk is issued and I try and report the sub while he's running down to first do I get to report my unreported substitute before the appeal.
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Desire4you