Recordar is transitive and always needs a direct object - "Yo recuerdo algo." Acordarse is intransitive and doesn't need a direct object - "Me acuerdo." If you want to add a direct object to Acordarse, you must use "de" - "te acuerdas de algo?"
Better use a dictionary. It's quite long to explain. The dictionary has good examples.
I find it helps to do litreral translations and say them to your self often in place of the grammatical english phrases. For example, start saying "from where are you" instead of "where are you from" or "I have hunger" instead of "I am hungry". That keeps the sentence structures and phrases fresh in my mind.
I believe acordar is to remember when it's reflexive (acordarse), but to agree when it's not.
Estoy de acuerdo = I agree
Lo me acuerdo = I remember it
Some verbs like acordar must be followed by "de" when there is a direct object as Juicy_Maffews explained above. Other verbs that also follow that rule are listed here: https://www.thoughtco.com/verbs-followed-by-de-and-an-infinitive-3079236
The subject "you" is implied by "tienes" and acordarte is a form of the infinitive reflexive acordarse with the te at the end indicating the verb is being done to "you" (informal/familiar). It is left at the end of the verb because you want to keep the inifinitive form since it follows the conjugated form of the verb "tener."
If you're explaining this to an English major perhaps this would be the way otherwise this is a lot of ❤❤❤❤❤❤❤❤❤
tienes que recordar que - is spanishdicts translation they say acordar is to agree ! so who is right ??
I was SO tempted to put "You must remember this" (A kiss is still a kiss....."