CMOS/BIOS user guide (basic)

Where can I download or find a copy of :
Basic BIOS UserGUIDE. I’d like to be able to go into bios and view and check thisngs out. Watnted to undersatnd how everything fits and works. Tips,examples,how to’s,ect.
I would like to educate myself insetting my BIOS for my PC to perform better.
Many ties people tell me to check you bios . I just don’t know where/how to start. What should I look for ? What can I change ??? , Ect. Any PFD or DOC out there I can download

Thanks !!
M.M.