Yes it appears the sambapos website documents have been moved and the original links are no longer available.
To track guest count:
Create a Ticket Tag: Manage > Ticket Tags > Add Ticket Tag
Name: Guest Count
Add a number of sub-tags depending on how many guests you want to allow on one ticket, see the attached screen shot, my restaurant has sub-tags number 1 through 16.
Add this tag to the department that will use Guest Count:
Manage > Departments > Edit Department
Ticket Tags Box > Add Tag Group
As you can see on the screenshot you have a tick box "Hide it on Reports", if this is selected the tag will not appear on any reports generated, otherwise when you run a work period report it will show the number of tickets generated with each sub-tag which you can add manually to track guest count.
When starting a new table you will have a button down the left-hand side labelled Guest Count.
If you want to add Guest Count to the receipts/kitchen tickets/bills just add the following to the relevant template:
Guest Count:{TICKETTAG:Guest Count}
Hope this is self-explanatory but if you need any help let me know