Search the show, then the episode
Try Rick and Morty S1E2 or the longer season and episode wording. Search uses the episode numbers recorded for this catalog. Open the episode guide to see the name and air date. The guide identifies the episode, while the viewing service determines its current availability.
Use one meaning for your checkpoint
Save the last completed episode, not the next episode you hope to start. Keeping that convention makes the reminder useful after a break. If you have only partly watched an episode, leave the checkpoint at the previous completed one and use the viewing player's resume feature where available.
Numbers and specials
Specials can be grouped differently across services, and not every title record includes them in the main season. Compare the episode name as well as its number. Do not mark an episode complete only because it is the latest entry shown.
Take the reminder with you
Checkpoints are local to this browser. They can be included in a Watchlist backup, but they do not automatically synchronize with a television app. Create a backup before switching browsers, or find your series.