New to all this?
Start with the whole approach behind Skill-Building Games.
See Skill-Building GamesLet the ball run underneath a relaxed foot rather than stamping down on it.
Teaching a child to stop the ball with the sole of the foot comes down to one mechanical cue: let the ball run underneath a relaxed, slightly raised foot rather than stamping straight down on top of it. Stamping either traps the ball awkwardly or lets it squirt away sideways.
I spent weeks telling him to just stop it with your foot before I actually watched what my own foot did with a rolling ball. I realised I was stamping down on top of it exactly the way he was, which was the actual problem, not his coordination.

The mechanic, plainly
Weight stays on the standing leg, and the receiving foot lifts slightly off the ground with the toes up, not flat, so the ball rolls underneath the sole and the sole simply closes over it, taking the pace out naturally.
Sole of the foot first touch football fails most often for one reason: a flat, stamped-down foot either traps the ball awkwardly under a dead weight or lets it deflect out sideways before the foot even makes proper contact.
What actually goes wrong
Stamping straight down on top of the ball is the single most common habit to fix, because it looks like the right instinct, get your foot on it, but does the opposite of what the sole technique needs. The fix is one cue: relax, don't stamp.
Different from the game you've already played
Roll the ball from a slight angle rather than straight on, so the child has to adjust the foot's angle to the ball's line instead of just reacting to its timing. The straight-on rolls in the first-touch freeze game don't isolate that adjustment.

Slow first, then live
This is a slow, deliberate drill first, and it's ready to use in a live game once it happens without thinking about it, not before. Rushing it into a fast game too early usually just brings the stamping habit straight back.
Quick answers
Lift the receiving foot slightly with toes up, let the ball run underneath, and let the sole close over it, rather than stamping straight down on top of it.
The most common cause is stamping flat-footed down on top of the ball instead of letting it roll underneath a relaxed, raised foot.
It's a small, precise movement, not a hard one, so it usually clicks quickly once the one cue, relax, don't stamp, replaces the instinct to stamp on the ball.
Keep going
Three places to go next, depending on what you're working on.
Start with the whole approach behind Skill-Building Games.
See Skill-Building GamesThe broader any-touch, dead-stop game this page's cue slots into.
See the practice gameChest and thigh control for a ball that isn't rolling.
See the aerial control guideTonight's five minutes
One cue, said out loud, fixes most of it tonight.