How to plan a path that visits a set of four waypoints within the map, located so as to avoid known obstacles/objects in the map.

edit

This is for an Introduction to Robotics assignment. I'm very new to ros so please forgive me if this is a simple question. Previously my teacher asked me to create a map from our classroom, using the robot scans. I used SLAM, with the command roslaunch turtlebot3_slam turtlebot3_slam.launch to obtain it. Now he asked us to make 4 waypoints in this map and plan a path that visits each, while avoiding obstacles in the map. My question is: is there any simple way to do it? I was able to use the turtlebot_navigation package to control the robot and give a single waypoint, but i have no Idea how to include several waypoints.