Office 365 user Calendar permission

Hi Folks,

i am asked to give a user access to all organization users calendar. This special user should be able to access anyone calendar and read their appointments/meetings or change them when necessary. I know that there is a way where you can grant permission in low level to a user to access calendar items except the private ones.

can someone tell me how or where i can find the script or cmdlet command to apply this?

Thanks!