It's a bit weird. The definite conjugation is only used if the object is a third person. So only with anything you call by name (Andrást, a lányt), and the pronouns őt, őket, önt, önöket, magát, magukat. For everything else (engem, téged, minket, titeket and their variants) you use indefinite, including the -lak/-lek form, where appropriate.
"Szeretni" means to like when talking about inanimate objects, food, pets... and to love when talking about two people.
- Te szeretsz engem? = "Do you love me?"
- Te kedvelsz engem? = "Do you like me?"
- Milyen zenét szeretsz? = "What kind of music do you like/love?"
- Milyen zenét kedvelsz? = "What kind of music do you like?"
There is another common formula to remember:
The thing or person that you like + 'tetszik' + yourself as the indirect object.
- Ő tetszik nekem. = "He/she" + 'tetszik' + "me." = "I like him/her."
Elsewhere in the course you will find szeretsz? just the one word by itself and the question mark. We are told that, usually, this means "do you love me?" without the need for "engem." Personally, given the scope for misunderstanding and the consequences, I find the use of "engem" rather reassuring. There again, by using "szeretsz?" alone, the questioner is left with a possible escape route if needed I suppose.