There's something that is often called a Session Zero. Session Zero covers topics like table rules (including any allergies or food intolerances), house rules, tone and genre for the campaign (including which topics the group would like to avoid, such as sexualized violence, violence towards kids, torture, and so on), the expectations of the GM to the players and their characters, and the expectations of the players to the GM.

A Session Zero is also a good way to make the players decide how their characters met and why they decided to go on adventures. It is, in essence, the bridge between each character's backstory and the start of play as a group.

You might decide that the player characters start play at the table of a tavern, while they're discussing what they need in order to start exploring the ruins or caves not far from the village. And then tell the players that they're responsible for deciding why and how their characters ended up there.

Perhaps all the characters got a cryptic letter with a time, date, and place - and a piece of a map. Signed someone they didn't know - and that curiosity made them meet up.

Maybe all the characters are members of the same society or guild, such as the Pathfinder Society in Golarion (depending on your setting, of course).

Perhaps all the characters are slaves together, and they need to break out of their holding cells and retrieve their gear before they get sold in the auction area of the stockade.

Maybe they've all been plagued by dreams about the terrible Gulthias tree and the citadel under the ground - and a feeling that they need to do something about it. These dreams and a yearning have forced them to go to Oakhurst - their teachers noting that it might be a sign from their god (cleric, paladin), an urging from their patron (warlock), or cursed by the gods or unlucky (rogue).