GPX Files
Export a GPX file from Strava (or any other activity tracker) for your run, bike, hike, or other activity. Then import the GPX file to update the model with your own activity track.
Printer Settings
Your default printer settings should be fine. 10% infill is sufficient, and you shouldn't need any supports.
Multi-color Printing
The color pickers on the website are for preview only — they won't be saved in the exported 3MF file. If you have a multi-material printer, use your slicer to print the model in your desired colors. If you don't have a multi-material printer, you can probably still achieve a multi-color print with a color change (a pause that allows you to change the filament).
