Remind  (erinnern an/jemanden erinnern) = when someone or something helps you remember.
“Can you remind me to buy milk?” (Kannst du mich daran erinnern, Milch zu kaufen?)

Remember (sich erinnern) = when you recall something yourself.
“I remember my very first English lesson.” (Ich erinnere mich an meinen ersten Englischunterricht.)

💡 Think of it this way:
Remind = needs two people or things
Remember = only needs one