1. click on either "run with forecast data" or "run with archived data" 2. choose a dataset that covers your area. 3. enter the lat./lon. of your station in the boxes provided 4. fill out the form for forward or backward, date/time, starting height of trajectories, and model duration. 5. click "Request trajectory" 6. write down your ID number and click "HYSPLIT run results" 7. This page will reload until the run is done (a few minutes) 8. the model is finished without errors when the link to "Trajectory plot" is shown.