From a safety perspective you always need to ensure that you have a map and compass (and obviously know how to use them) for alpine or multi-day hikes, such as this. If you are using an app, for a quick location reference, I have personally used Memory Maps and Pocket Earth as these allow you to import GPX files. Pocket earth is only available on iPhone so if you are on android I’d suggest searching for an app that allows for track importing and offline use (with topographic detail). Please don’t ever use an app as your sole or primary navigation tool. If you don’t know how to use a map and compass I would suggest gaining experience with these tools before heading out on the trail.