I would like to restrict access to a sub-folder under a main folder to only allow myself access to it, how can I do that?
The group that I am in has access to /Parent_Folder and I have
created a sub-folder called /Parent_Folder/Child_Folder/ which I want to
be the only one that has access to.
There are no simple way to protect a folder.
But you can easily prevent other users to access different objects.
For this just right click on your object then go to properties / authorization.
Here you need to add your user name and complete all the boxes.
Then apply and press OK.
Only the username specified will have access.