Understanding how the NBA playoffs work isn't as linear as some people believe. It starts with an understanding of the regular season. Many factors are involved with a team's placement in the post season. A team having a winning season (winning more than 50 percent of their games) doesn't necessarily guarantee them a spot in the NBA playoffs.
The NBA is divided into halves, the Eastern and Western Conferences. Each conference is made up of three divisions. Teams are placed into the divisions based on their locations. Although overall win/loss record in the regular season is important, it is more important for a team to have a better win loss record than teams in their respective divisions. The funny aspect of this division is, if your lucky enough to be in a region housing weak teams, it's easier for your team to make the playoffs. Which is why we see certain mediocre teams getting killed by the elite teams in the playoffs.
It should also be mentioned that Eastern Conference teams play teams of the Western Conference throughout the season. But the win/loss records of each team are only important when compared to teams within their respective conference. Say the Los Angeles Lakers win ten more games than the Cleveland Cavaliers in any given year. The Lakers record will not change where Cleveland lands in the NBA playoffs, because the teams play in different conferences.
A total of sixteen teams make it to the NBA playoffs. Eight teams represent the Eastern and Western Conferences respectively. A team's positioning in the playoffs is called its seed. There are eight seeds. The higher the seed, the better the team.
If an NBA ball club wins its division (i.e. having the best record in its division), it's guaranteed a seed no lower than fourth in the NBA playoffs. The rest of the seeds are made up of the remaining teams in the conference with the best records.
At the end of the 82-game regular season, the NBA playoffs begin. The top eight teams of the Eastern Conference battle it out to see which team will represent the East in the NBA Finals. The Top teams in the West will do the same.
There are a total of three rounds in the playoffs. In the first round, the first seeded team plays the eight, the second plays the seventh, the third faces the sixth, and fourth and fifth are matched up. Each series is a best-of-seven series. The first team to win four games advances to the next round of the NBA playoffs. Then wash, rinse, repeat for two more rounds.
The home court advantage is determined by record, regardless of seed. The first two games of the series are played on the court of the team with the home court advantage. The next two are played at the opponents place. If more games are needed to decide the outcome of the series, the next game is played on the court of the team with home court advantage and continue at the other team's place. The seventh, and final game (if needed), is played in front of the fans for the team with the home court advantage. In the event that both teams have the same win loss record, a head to head match up is used to determine who'll receive the home court advantage. The team with more victories over its current opponent will receive the home court advantage.
The four remaining teams face off in the second round of the playoffs known as the conference semi-finals. The same format applies. The two winning teams in this round will advance and face each other in the Conference Finals.
The two teams left standing gets to represent its conference in the NBA Finals. Once again, home court advantage is determined by record. The first two games are played on the court of the team with home court advantage. The next three, however, are played for at the other ball clubs arena, with the final two (if needed) being played in front of the crowd cheering for the team with home court advantage.