tf, pending any other input here, I am not aware of any such material apart from, perhaps, a few admin and financial instructions relating to the rank in specific companies. Assuming you are a suitably qualified FO, (as opposed to someone about to set-up a new command course!) you already have the same licence as your colleague in the left seat and you take the same periodic proficiency tests and courses. According to your time on type, your technical and regulatory knowledge should be similar - better even!
Depending on the culture in which you have flown so far, you have been allowed, even encouraged, to make decisions during your time as P1. Your impending upgrade is, one would assume, because your employer believes that you have already proved yourself capable of taking on the additional responsibilities of command which, in simplicity, boil down to <The Buck Stops Here>.
There may be a company document somewhere titled, "Global Airlines Guide To Perfect Captaincy" (similar titles abound on English cricket!). Perhaps one of the usual aviation suspects has published, "How To Be A Super Airline Captain" to add to his collection of previous tomes of limited content.
The best study material is a thorough revision of all your company ops manuals and procedures.
For wider reading, "Handling The Big Jets" by D P Davies is an excellent technical book. In spite of its age, E K Gann's "Fate Is The Hunter" remains the most astute command bible of transport aviation ever published. It is still available from online sources.
Hope this helps, and good luck.