Imagine you're going to a big party with your friends. This party has different levels or tiers. Tier 1 is like the ground floor of the party, where people come in and start having fun. Tier 2 is where the party starts to get a little more exciting, with music and dancing. Tier 3 is the top level of the party - it's like the coolest part where the music is really loud, and people are dancing like crazy.
Now, imagine this party is actually a nightclub. A Tier 3 nightclub is a very exclusive and fancy club where only certain people can go. You have to be 21 years old or older to go to a nightclub, and you need to dress up in fancy clothes to fit in with the other people there. The nightclub has different rooms with different music, bars with drinks, and places to dance.
A Tier 3 nightclub is different from other levels of nightclubs because it's usually more expensive to get in and the people there are usually more famous or important. Imagine going to a party where only the coolest and most important people were allowed- that's what a Tier 3 nightclub is like. Overall, it's just a really fun and exciting place to go for a night out with friends.