How can I restrict people from accessing the general channel?

By default all regular members are added to the general channel when they join Pumble. In order to restrict a user from accessing the general channel, you can change their role to a guest (single-channel or multi-channel) and not include the general channel when choosing the channel(s) they can access. Also, when inviting a new user, you can invite them as a guest and choose not to add them to the general channel.