The whole idea is that when you touch an object, you must only say one number. That’s called one-to-one correspondence. This can be tricky for little learners. Often their hand and mouth don’t move at the same rate of speed. I would offer a couple of suggestions.
Here’s the first one. Practice placing all of the objects in a single horizontal line with a slight space between them. I think 5 might be a good starting number if the child can count out loud to 5. Model counting like this for the child. Touch the first object and say “one”. Go slowly and touch each object (one at a time) and say the next number. Let the child practice.
Here’s another way. Put all of the objects in that same single horizontal line. This time as you model counting out loud, slightly move the object. As you count each object, move it just a little. Let the child practice.
Here’s one more way. Put all of the objects in that same single horizontal line. This time model counting out loud as you move the object a noticeable amount and make a new horizontal line. Let the child practice.
As the child is successful with the counting strategies, increase the rigor by counting to a higher number. Make learning fun by using cute erasers, cookies, jelly beans or cereal.