Greek doesn't say "I like X"; it says "X is pleasing to me". The thing you like is the subject, so use αρέσει for one thing and αρέσουν for several, and put μου, σου, του/της in front for the person.
Examples
- Μου αρέσει ο καφές.
- I like coffee.
- Μου αρέσουν τα ταξίδια.
- I like travelling.
- Της αρέσει να διαβάζει το βράδυ.
- She likes reading in the evening.
The mistake to avoid
Saying "Εγώ αρέσω τον καφέ" — that would mean the coffee likes you; the verb agrees with the thing, not with you.
Where this fits in
Προτιμήσεις και ελεύθερος χρόνος, Greek A2: Talk about hobbies, likes and dislikes, and free-time plans.