1. Purchase and install Homecoming for Mastodon in the App Store.
2. Open the Safari address bar popup.
3. Select Manage Extensions.
4. Enable Homecoming for Mastodon.
5. Open the Safari address bar popup.
6. Select Homecoming for Mastodon.
7. Enter the domain of your Mastodon instance and save. (Homecoming for Mastodon may autofill the domain from the open web page, but you still need to save.)
8. Now whenever you're browsing a web page on another Mastodon instance, you can just tap the Homecoming for Mastodon extension icon.
9. The page opens in your own Mastodon instance. This works for any Mastodon URL, including profiles and posts!
You only need to enable Homecoming for Mastodon once in Safari, and then it will remain enabled permanently. It will remain enabled even after you install new versions of iOS and Homecoming for Mastodon. If you ever need to disable Homecoming for Mastodon, select Manage Extensions from Safari's address bar.