Boston Celtics guard Terry Rozier (12) celebrates after a basket against the Milwaukee Bucks during the fourth quarter of Game 7 of an NBA basketball first-round playoff series in Boston, Saturday, April 28, 2018. At right is Bucks guard Jason Terry. The Celtics won 112-96, eliminating the Bucks from the playoffs. (AP Photo/Charles Krupa)
Boston Celtics guard Terry Rozier (12) celebrates after a basket against the Milwaukee Bucks during the fourth quarter of Game 7 of an NBA basketball first-round playoff series in Boston, Saturday, April 28, 2018. At right is Bucks guard Jason Terry. The Celtics won 112-96, eliminating the Bucks from the playoffs. (AP Photo/Charles Krupa) Credit: Charles Krupa

WALTHAM — Ben Simmons and Joel Embiid are about to find out what the NBA playoffs are really about.

After dispatching the Miami Heat in five games in the first round in their first career postseason appearance, the Philadelphia 76ers’ youngsters will open the Eastern Conference semifinals on tonight in Boston against the Celtics.

All those banners hanging from the Garden rafters.

All that history on the parquet floor.

All that bad blood between the two cities.

A civic rivalry that dates back to the Revolutionary War era came of age on the basketball court with Wilt Chamberlain leading the Philadelphia Warriors, and later the 76ers, against Bill Russell’s Celtics in the 1960s. Larry Bird and Julius Erving picked it up in the 1980s.

Celtics forward Marcus Morris, a Philadelphia native, grew up watching the Allen Iverson-led 76ers that went to the NBA Finals in 2001 but lost to Paul Pierce and Antoine Walker’s Celtics in the Eastern Conference finals the following year.

He’s not expecting any favors from his hometown crowd.

“I’m expecting the same treatment as far as them not even caring that I’m from Philadelphia,” he said after practice on Sunday, a day after the Celtics advanced by eliminating the Milwaukee Bucks in Game 7 of their first-round series. “I really don’t care either, when I’m competing against them.”

The franchises have met 19 times in the playoffs (though only three times in the past 33 years), with Boston holding a 12-7 edge.

YOUTH IS SERVED

Two years after winning just 10 games, the Process is paying off for the 76ers.

Embiid, the third overall pick in 2014, returned after missing the first two games of the playoffs and averaged 18.7 points and 10.3 rebounds in three wins over Miami.

Simmons, the No. 1 overall pick in 2016 before missing all of last season, averaged 18.2 points and 10.6 rebounds against the Heat