Here is the official description for the Science skill:
[ +- ] Science
The Science skill covers academic and practical knowledge, but is practically applied in the wasteland through computer coding, robotic programming, and brewing chems.
Its default S.P.E.C.I.A.L. attribute is Intelligence but you might use it with Perception to observe a test subject, or Charisma to convince people of something using your scientific knowledge. You use Science to hack computers, brew chems, and solve problems with science!
And honestly, I’m not sure how useful the Pilot skill is gonna be. It’s used for "driving land vehicles, or pilot flying vehicles", vehicles like vertibirds, tanks, cars, and motorcycles are the examples it gives. The games don’t feature working vehicles except for vertibirds really, and having cars and stuff kinda ruins the whole exploration thing I feel like, it’s almost like fast travel.
During character creation, no skills can be increased above the rank of 3. Tagged skills start at 2 and everything else starts at 0. I highly recommend buying that third rank for all of your tagged skills first.