Catalan doesn't say "I like X"; it says "X pleases me". Put a pronoun (m', t', li, ens, us, els) before agrada, and make the verb agree with the thing liked: agrada for one thing or an infinitive, agraden for several.
Examples
- M'agrada el futbol.
- I like football.
- M'agraden els llibres d'història.
- I like history books.
- A la Marta li agrada cuinar.
- Marta likes cooking.
- No ens agrada gens el fred.
- We don't like the cold at all.
The mistake to avoid
Never say *jo agrado el futbol* — the liker is the pronoun, not the subject.
Where this fits in
Aficions i temps lliure, Catalan A2: Talk about hobbies, likes and dislikes, and free-time plans.