I am DMing the one-shot Peril in Pinebrook. The game is designed for 4 players, but in the oneshot, it says at one point:

If you have more than four players, they can change the names and descriptions on a duplicate character sheet so that they’ll have unique characters with similar abilities and equipment.

I have never DMed before. I want to adjust the one-shot for 5 players, even though it is meant for 4 players. Do I need to adjust the hit points of the enemies, the DCs of any other events, etc.?

Is there perhaps a formula that is available to automatically adjust hit points and DCs in one-shots to the number of extra players that might be added in the future?