A mobile robot travels inside a multi-storey building. The robot does not know an environment a priory; it explores each floor via lidar and SLAM method. As a result, it has access to the map of the entire building. The robot can also determine staircases and move along them using data from RGB-D camera. The objective is to reach a given location, which is specified by the operator based on the resulting map. We present a navigation and guidance strategy under which the robot autonomously reaches the desired location combining 2D path planning algorithm with staircase overpassing. Effectiveness of such strategy is also confirmed by real-world experiments with tracked robotic platform.