Poke around, and consider if training to be a mentor to someone who is incarcerated feels like the right thing for you. A new mentor training program - PIP, the Prisoner Interaction Program - will be convening in January. All online.
The training is done online via zoom audio video conferencing. Tentatively, The training would be once a week for about an hour over a six week period at the end of the training I asked people to write a 200 word thesis on topics that I give. Then you get a certification as a mentor with a nifty certificate and then you’re on your way. As inmates pop up, I assign them to a mentor and see how it goes.
Regarding books, prisons don’t usually allow used books because they have to come from a publisher of some sort, such as suluk press or Amazon, so donations to the prison book project are usually cash or check. if you wish to donate books, I could send them to probationers or parolees after they are released, thereby getting around the used book
You may go online to the kinship website, fill out a mentor application, and download and read the introduction to the mentoring program which will give you a better idea of the program.