Tap on 'More' on the bottom menu

Tap on 'Diary'

Tap the '+' icon to add a new note

Enter the desired information and tap on 'Type' to set the category if applicable.

Tap on your "More" icon and tap "Notes"

Tap on the 'Add a note' on the bottom of the screen and type your entry

Tap on "General" to choose a note type: allergy, emergency, mood, general, or side effects