Archery substitutes for Firearms. For improvised cannons and the like, use Strength + Athletics to actually fire the thing after someone lines it up with Wits + Enigmas. Ancient Imperial ranged weapons are treated like crossbows and use Archery as normal.
Ride substitutes for Drive. Each mount has a handling score (with higher meaning smarter and more compliant, lower meaning dumber and more stubborn). Common pools:
Pursue: Manipulation + Ride + Handling
Jumps/tricks: Presence + Ride + Handling
Tail: Wits + Ride + Handling
Enigmas substitutes for Computers. This is mostly used for puzzle-solving, network-untangling, and number-crunching.
This is a non-modern world, and as such literacy isn’t assumed. Especially learned people eventually learn Old Imperial, the formal high tongue of the ruined empire, and can even learn to speak it.
Two total dots: The character has literacy.
Three dots in either: character can read Old Imperial.
Three dots in both: character can speak Old Imperial.
Medicine works the same as normal if inside a city with access to proper medical facilities, with a -4 penalty to surgery or treating serious wounds.
If such a facility isn’t available, treating serious (aggravated) wounds is handled by the patient rolling to survive rather than someone rolling to treat the injury. This is an extended Resolve + Composure action that can be aided by Intelligence + Medicine rolls at -6. All medical stuff other than treating simple wounds is at a -6 penalty.