If you are a beginner, all you need is 3 minutes (2-3 times per week) to start. Increase your workout slowly, meaning in week 3, you'll progress to 5 minutes (2-3 times per week), in week 5 you'll start staircase running for 7 minutes (2-3 times a week), and so on. Listen to your body, listen to your joints. If you need longer to recover or longer to get used to the exercises then progress even slower. Your health always takes priority.
But even if you are well-trained, allow your body and especially your joints, if you are new to this type of training, a sufficient amount of time to get used to these exercises, meaning, don't overdue it. And don't neglect to warm up, cool-down, stretch and take water breaks as needed; these are important components of a solid workout. Listen to your body, take rest when needed and don't forget to have fun.
Basic staircase workout: