Ensure that your switch has port forwarding enabled for the IP address the SFTP user will connect to (for example, port 49152). Note: port forwarding is TCP, not UDP.
Ensure that your Jellyfish also has an internet connection (you can confirm this under Integrations within Jellyfish Manager).
Navigate to Jellyfish Manager > Integrations -> SFTP.
Click the setup button and then install.
After the install is finished fill out the two required fields.
Server Port - Insert the forwarded port from step 1.
Path - The base directory users will be placed when connecting the Jellyfish.
Click save, and then the SFTP service is setup and ready to go.