Set waypoint for plane in guided mode

Hello everyone, I am flying a sim via Mission Planner. On these flights, my plane was normally in “AUTO” mode, so I used the following command:
Command(0, 0, 0, mavutil.mavlink.MAV_FRAME_GLOBAL_RELATIVE_ALT, mavutil.mavlink.MAV_CMD_NAV_WAYPOINT, 0, 0, 0, 0, 0, 0, a , b, 70))

However, now I need to send waypoints to the plane in “GUIDED” mode. That’s why I can’t use the code above. On the internet they suggested me to use MAV_CMD_DO_REPOSITION instead of MAV_CMD_NAV_WAYPOINT. But I couldn’t find a way out either way. I use plane in sim and send my commands/messages via Python. What path do you think I should follow?

i’ve found that way but couldnt figure out how to implement it

Hello, could you solve the problem? If you did, can you please get me back?