2

It doesn’t sounds right. If you have access to setup port forwarding in your router, why do you want to port forwarding again in your slate?

In theory it is simple:

  1. Set port forwarding at your ISP router: ISPWAN:[port] to [slateip][:[port] …
  2. Set port forwarding at your slate SLATEWAN:[port] to [destinationip]:[port]

But these are not standard ports. We don’t know the service behind. If the service is doing some kind of MITM check or crypto things, it may won’t work, even if the forwarding works correct.