Since the tabletop game is officially out of print (OOP), various community-led projects have archived and updated these rules in PDF format: Battlefleet Gothic Rulebooks 25 Feb 2021 —
If you search for "Battlefleet Gothic Armada PDF" and find a 20-page manual with screenshots, you have the video game manual. Close it and search for "BFG tabletop rules PDF." The key difference: the tabletop PDF will have tables for "Weapon Battery Strength" and "Armor Values" (Front/Side/Rear). battlefleet gothic armada pdf