Can anyone find this book in PDF format preferably, thanks. Will pay $5-$10 https://www.amazon.com/Embedded-Cortex-M-Microcontrollers-Assembly-Language/dp/0982692668/ref=dp_ob_title_bk?dpID=51%252BE9C%252BHCoL&preST=_SX258_BO1,204,203,200_QL70_&dpSrc=detail
I learned to use STM32 microcontrollers in my college classes. My professor wrote a book about ARM Cortex M that I found helpful. He also has a website with some sample lab and info here that might help if you choose this route.
His lab info is based around the STM32L476xx instead of the STMF series.
https://www.amazon.com/dp/0982692668/ref=cm_sw_r_sms_apa_i_3.QvDb45VCMYC
https://www.amazon.com/dp/0128015071/ref=cm_sw_r_sms_apa_i_sbRvDbK9J2Q73
The former is a fantastic book teaching you a specific microcontroller (but the concepts are not cortex-m4-specific). This is the microcontroller we used in my undergrad. You can get Discovery boards with this microcontroller alongside that book. STMicro makes a couple different boards for decent prices.