I don’t have the books handy, but I can say a few things. They’re definitely in there.

-You cannot increase characteristics after character creation, except by a couple means: first, “dedication”. That does mean that, generally, characteristics won’t be increasing until you get far down a talent tree and find the Dedication talent. Second, cybernetic implants can increase characteristics. So yeah, after initially spending on characteristics at character creation, your advancement options are limited there.

-Skills can be increased at any time. The costs depend on whether they’re career skills or not. It’s pretty simple for career skills…the cost is 5 times the rank you’re buying. So if you’re buying rank 1, it’s 5 xp. Rank 2 is 10 xp, Rank 3 is 15 xp, and so on…

Mind you, that’s additive. So you buy each rank in sequence. So getting from rank zero to rank three in a career skill would be a total of 30 xp.

For non-career skills, the formula is rank times 5, plus another 5. So instead of 5 -> 10 -> 15, it’s 10 -> 15 -> 20 xp.