In my case, I wanted to perform scheduled reboots on the same group of servers on a recurring basis. One of the ways of storing the names of these servers was through the in-built Computer Groups area, so I will go through creating using that method.
There are many ways of populating a list of servers for your runbook to run against, ie. From an AD Group, a SharePoint list or a text file.
1. Navigate to Computer Groups in the left navigation pane.
You can create your own folders to store your Computer Groups but that is personal preference.
2. Right-Click the folder you want to store your Computer Group in, and click New > Computer Group
3. You can then give the group a name and description in the General Tab
4. In the Contents tab you can add the computers by name. There does not appear to be a need to add Fully Qualified Domain Names. If the Computer does not show up via the search button then you can just type the name in. Click Finish once done.
5. To use the Computer Group, within the activity that you wish to use it with, right click in the field and select Subscribe > Computer Group and find your Computer Group.