Well, one must be careful when using "the". "The" is specific: it tells us that the noun is already known and familiar, or at least very obvious. I initially misread your example sentence as "candles", but I'll still use "candles" as my example, because "candy" is uncountable and using "candies" would just confuse you more. I like candles = general meaning. I like the candles = a specific set of candles. Maybe the ones in a room design or on a cake. The listener would already know which group of candles you mean. I'm watching TV = viewing in general. I'm watching the TV = a specific television. PS. In English, the "I" (io) is always a capital letter.

What do you mean by "singular and plural names"? Are you referring to NOUNS? "The" in English has the same meaning as it has in Italian. The rules of use are the same. Only there are a few small differences. I suggest you learn the differences between English and Italian usage. It's much easier.