If you don't have a channel yet, it's easy to create one. In Telegram, find the New Channel button in the toggle menu at the top left screen corner.
When you're done, hit Next.
Make sure the channel is set to Private. There's no need to share the channel's permanent link, the InviteMemberBot will take care of this.
To finish, hit Done.
Congratulations! This is how your new channel should look: