To create the root directory for your packages first you need to allocate an additional disk or specify a folder on your current server. (Do not create the share on the same server that the sequencer is installed on.)
Once done you will need to right click the directory and select share with > specific people:
Now we have to specify who we want to share the folder with, I would suggest using a Security group for your App-V admins and give the group Read/Write access.
You will also need to give your App-V Server permission to access this share, right click the directory and select share with > specific people and type in your App-V Server name. An example of this: YourDomain\appv-server$ or appv-server$ (The $ indicates that you are adding a computer account)
Once the directory has been shared out then add the share to the sequencer as the Q drive.