craigman66 Sorry for the late reply.
There is a parameter in the properties file you can change for this. Unfortunately orchid does not support multiple archive directories so if you don't want to lose your existing footage you will have to manually copy them to your usb drive.
The process for safely changing the archive location(where the footage gets recorded to) is as follows:
old archive directory: /orchives
new archive directory: /mnt/my_usb
1. Stop service.
sudo systemctl stop orchid
2. Copy old archives from /orchives to /mnt/my_usb
sudo cp -r /orchives /mnt/my_usb
3. In the properties file: /etc/opt/orchid_server.properties
Change the path of archives.dir to point to your mounted usb drive.
archives.dir = /mnt/my_usb
4. Start your server.
sudo systemctl start orchid
Now orchid will record all future footage to /mnt/my_usb.