If you took notes after clicking the in-app popup notification about taking notes in conference, those notes are on the page for each session under General Conference > April 2020. For example, inside that conference, tap on Saturday Morning Session. You should see a note icon next to where it says "Record Your Impressions."
These notes, and all other notes you've taken in the app, as well as highlights you've created, etc. should also be available under Notes > All (the Notes section is on the home Library screen). If you're signed in with your Church Account, you should also be able to find your notes at
Study.ChurchofJesusChrist.org or
Notes.ChurchofJesusChrist.org.