Count on from your square as many squares as the die shows. Touch each square as you go, then you will not miscount.
If you land at the foot of a ladder, you climb up. If you land at the top of a slide, you slide down.
You only jump once - you stay on the new square.
Example
For parents
What does this exercise practice?
Snakes and ladders practices counting on and adding up to 20 and then looking a number up - arithmetic with a second step.
Common pitfalls
The starting square often gets counted as well. But the first step you count is already the square after it.
How to practice at home
Play a real game of snakes and ladders and count out loud on every turn; whoever lands on a ladder says in advance where they will come out.