Hi Ash,
You need to have PF3 Display turned on, then you can start Web Display - PF3 needs to be running and connected to FS.
Having done that you can access Web Display from a browser on your Android tablet using a URL similar to this: http://<IP address>:7339/
<IP address> is the IP address of the PF3 PC on your local network and assumes that the default port (7339) is available to use.
Full details are provided in the documentation that is installed with the Web Display program, but do come back if you have any further queries.
Cheers,
Martin