Setting up a role-exclusive channel is integral to conducting official guild business without alarming the rest of the troops. With the correct settings, your guild members shall not pass without your explicit permission.
Step 1: Create a role (Optional)
If you already have a role that you'd like to give super special access to, then skip the creation step and move on to step 2.
If you do not already have a role set up that deserves this exclusive status, then open Server Settings > Roles and create a new role for your secret channel by clicking the "+" sign next to Roles.
Step 2: Administer Role
Next, open the "Members" tab and use your sorting hat abilities to administer this new role to the appropriate people by clicking on the "+" sign next to their name then selecting the new role (in this example, "Leader" role) from the drop down menu.
Note: If you don't see any or all names in the members tab, make sure that @everyone is selected in the top right.
Step 3: Create a Super Secret channel
Click on the "+" icon next to "Text Channels."
Type in the new channel name and select the role that has a VIP pass and will only be able to access this channel. Finally, click create.
Now members with the "Leaders" role are the only people who have access to this channel! Users who do not have the ability to access this channel will not see it on their channel list.
To add a role exclusive voice channel, follow these same steps except create a new voice channel instead of text channel by clicking the "+" button next to "Voice channels."
Once you click the "+" button, the same window will appear as above asking for the new channel name, as well as selecting which role(s) you'd like to give channel access to.
What does it all mean, Discord?
This box is meant to make your life easier by setting up basic channel permissions for you, thus allowing restricted access to the role or roles that are selected. To find out which permissions are adjusted, click on the cog wheel icon next to the channel you just created.
Next, click on the "Permissions" tab and you'll see that the @everyone role has been denied permissions to "read messages."
Likewise, clicking on the role that's been given access to the channel will show that they have been granted permission to "read messages."
The difference in the basic permissions for a voice channel versus a text channel is instead of "read messages," the "connect" permission will either be green-lighted or denied.
Unlike text channels, people who can't access a voice channel will still be able to see the channel in their list. Upon hovering their cursor over the channel name though, they'll be greeted with a big fat no (aka circle with a slash).