That's a very difficult question
For a kid, a staircase in a house can become a dangerous place - steps turn into an obstacle course, handrails into fascinating slides from which they slide down, fences into a climbing wall. Do not hope that a strict prohibition of games on the stairs will cause the child to be careful. The only way to protect him is to put the best baby gates for stairs. However, when choosing a gate you need to pay special attention to the castle - by copying the behavior of the parents the child may open it and be in danger. It is better that the doors open with a triple action or snap automatically.
Hmm well you can carry your child when you walk upstairs.