You can review the concept of counting out by watching the video below.
You will need: several small items such as pom-poms, Lego bricks or pasta, a dice, two bowls or plates
If you don’t have a dice, you can use this online dice.
Click on the image to access the dice
Place the items in a pile. Give a plate to each player. The first player rolls the dice and takes the number of items matching the number on the dice. The other player has a go. Repeat until all the items are gone.