Look for a resource pack that you'd like to install to your server and then copy the Direct Download link of the pack.
The Resource Pack link must be a Direct Download, meaning that if you go to that link then the file download will start.
Now log in to your WiseHosting Game Panel here and Stop your server.
Then open up the Properties -> Admin tab
Search for the Resource-Pack tab and just paste the direct download link of the resource pack there.
Now start up your server again and players should see a pop up upon joining the server that lets them easily download and apply your chosen pack.
If you have any issues uploading your world or accessing the SFTP then please contact us through the Support Tickets.