Learn Italian: Ci vuole una stanza vuota per praticare in sicurezza. - You need an empty room to practice safely.

Ci vuole comes from the verb volerci and is used for general or objective necessity, meaning "it takes" or "one requires." It describes what is needed to complete a task regardless of who is doing it. Hai bisogno di would imply a specific, personal need (e.g., you, personally, are in need of a room right now). The "you" in the English translation here is the general "you."

What is the subject of vuole in this sentence?

The subject is actually the thing that is needed: una stanza vuota (an empty room). With volerci, the thing required acts as the subject. Since one room is singular, the verb is conjugated in the third-person singular (ci vuole). If you needed two rooms, it would be plural: ci vogliono due stanze.

Why do we use the phrase in sicurezza instead of an adverb like sicuramente to mean "safely"?

In Italian, sicuramente is a false friend for "safely"; it actually translates to "certainly" or "surely." To express doing something safely or in a safe environment, Italian commonly uses the noun phrase in sicurezza (literally, "in safety").

Why is per used before praticare?