In an individual Pokemon's stat screen, you'll see a semi-circle at the top.
Interestingly, different Pokemon require you walk different distances.
That's why it's important to catch as many Pokemon as you can, so you can whittle them down to the.
Plus, when you capture them you get bonus Stardust.
You can quickly join the website and allow it to access your location to instantly get a list of nearby available trainers! The 10K eggs get you more powerful, uncommon ones like Snorlax.
You'll get a message that asks if you're absolutely sure you want to swap buddies.