In the classes section of the Rulebook there is an entry for Skills (on the right hand side of the first page for each class) stating "Trained in a number of skills equal to (some number) plus your Intelligence modifier". Where (in the book) is it explained what this entry means? I'm interested in a page number.
For a sorcerer, for example, the 'some number' is 5 plus the Intelligence modifier (let's say her INT is +2). So this sorcerer is trained in 7 skills. But according to her class, ancestry and background, she is only trained in 6 skills (5 of them signature skills) not 7. How does she know which other skill she is trained in? I can't find anything in the book which explains this.
Check the errata. The rules you are citing have been replaced.
But you may freely select which skills you are trained in unless specific skills are named directly or indirectly. For example, the latest rules update gives sorcerers the following:
"Trained in two skills determined by your bloodline.
Trained in a number of additional skills equal to 3 plus your
Intelligence modifier."
The two bloodline skills are named for each bloodline, while the others can be freely chosen from any of the skills in the game.
And by "named" here, we mean the skills that (formerly) read "signature skills."
The concept of "signature" skills is gone.
But you would definitely need to look at the errata to know the bloodline skills, as the original rules had four per bloodline and the latest errata only have two.
Oh, yeah, I forgot about that. I use the review/annotation tools to markup my PDF.