Train for a 5K
If you are just trying to get started towards running a 5K, you can use a popular Couch to 5K running plan on your wrist. The Run 5K app isn't the same Couch to 5K app that comes up first in the app store, but it does deliver the same plan on your wrist.
A Couch to 5K apple Watch app means you can glance at your wrist to see how much longer you need to jog, check your timing and your heart rate. The Run 5K app is free in the App Store.