IBM 5160  -  Basics, for 5160 beginners

This is a slow computer.  BE PATIENT.  After turn-on, it can be minutes before an error message is displayed.
An AT-class keyboard will not work.  You need an XT-class one, or one that can switch between AT-class and XT-class.     (Or AT-class one together with a protocol changing adapter.)

NOTE:  It is known that some IBM 'Model M' keyboards will work with the 5160, but to work, the BIOS in the 5160 needs to be one of the later revisions.
The IBM supplied floppy controller and 5.25" floppy drive are single density.  They will not read high density 5.25" floppies, such as 1.2M (2SHD) ones.
There is no 'CMOS SETUP'.  All motherboard configuration is done via switches/jumpers.
There is no real-time clock (RTC) on the motherboard or on IBM-supplied expansion cards.
After turning off the 5160's power supply, wait at least 1 second if you are planning to turn it back on.  Any shorter; the 5160 may not start.
Expansion slot 8 is different to the other slots.  Most cards do not work in slot 8.  More information at here.
The 5160 motherboard does not have a keyboard controller chip.  Instead, it uses discrete components - see here.
The power-on self test (POST) of an IBM 5160 motherboard outputs only a few POST codes and does so to port 60h.  I have yet to see a POST card that monitors port 60h.
Aged tantalum capacitors are known to explode.  That has happened to me many times, particularly when I have acquired something that has not been powered on in years.  If the motherboard, or expansion cards, are exposed to your face when you power them on, then consider wearing eye protection.  More information at here.