Where is the Migrate UI page? In Drupal 8.2.x there is the new migration UI tool. I've enabled it, but I can't find any link going to any UI page. Back in Drupal 7 when you enabled a module, it would have a configure link next to the module name in the modules page, but Drupal 8 doesn't. How would one find these configure links to the module pages?
modules -> migrate UI -> configure.

Press on the gear and you will enter the migration process.