Questions & Answers about Я медленно поднимаюсь по лестнице.
поднимаюсь is imperfective aspect, indicating an ongoing action. To express that you’ve already climbed (a completed action), use the perfective verb подняться. For example:
Я медленно поднимусь по лестнице. (“I will slowly climb up the stairs” or “I slowly climbed up the stairs.”)