I have done this many times in multiplayer. The best way I know how to accomplish this is to go to the File menu once you have entered the sim. From there select the Flight Planner option and complete the required information and save the flight route. Once you have finished this, enter back into the sim and look at your right multi function display or MFD. Located near the top right of the right MFD, you should see the letters "WPT" for waypoint. Click on the corresponding button then press the button next to the letters "SEQ" for sequence. From there, you should see your planned route displayed on the MFD. You should also see some of the information such as the heading bug, selected waypoint, time and distance displayed on your Heads Up Display (HUD). Hope this helps.