Click on the Settings button ⚙️ next to the 'Week' button > select '🛡️Permissions'. A new dialog will pop up.
If you want everyone in the channel to be able to modify Calendar Pro, please select 'Everybody in this channel can add/edit events' > Save.
If you prefer the owner to retain exclusive editing rights to Calendar Pro, please select 'Only the creator of this Calendar Pro can add/edit events' > Save.
ℹ️ The creator is the individual who added the Calendar Pro tab, and there is only one creator for each tab.
⚠️Currently, granular/selective permissions are not available. For example, it's not possible to allow some users to add events but not delete them, or to assign different permission levels to different users.
If you'd like to see this kind of detailed control over permissions in the future, we encourage you to suggest it on ideas.teams-pro.com