1. The opening should be to the front. (I suppose there are tie-strings there.)
2. Turn the pants around.
3. Make sure they are not inside-out. The logo is on the outside.
4. Step into the pants, one leg at a time.
5. The logo should be on the front.
Perhaps a toddler won't know the word "logo." Just name the logo picture eg. Mickey is on the outside.