How to upload GPX route into Gaia GPS
Find GPX file from website
Download to phone. *(example using iPhone, Android might be diffrent)
Open downloaded file with Gaia GPS
Click Open with
Click More
Click "Copy to Gaia GPS"
Make sure status "complete" and file appear in app
Click on loaded GPX file and click "show on map"
For others route you can look into;
Good luck
