To invite new members to your hub, go to the settings section of your hub, select Invitations from the left hand navigation, then click "invite new people". Note: You will need to be an administrator to access this feature.
On the invite new members section you can invite new people by entering their email address, or grant access to additional channels by entering the name of a member who is already in your account.
When entering an email address or a name, once the value is correct, a drop down box will appear below the text field:
You must click on this box to add the person to the list of invites. If you don't click on it, the person / email address will not be invited.
When inviting new members to a network, they will automatically have access to all open and public channels in your network.
The list of open and public networks will be listed in bold. If you'd like to add private channels that they should have access to, you can click on the link "...give them access to additional channels" and a selection box will appear where you can type in the name of private channels: