You will need: keys "13", "17".
Disconnect all cardan shafts from the transfer case
Removing the cardan shaft is discussed in the article - "Removing and lubricating the cardan shaft"
In the car, disconnect the transfer case lever boot from the tunnel casing
Remove the cover together with the lever handle.
Remove rubber boot of the lever.
Unscrew the nuts securing the left side cushion of the gearbox suspension to the body and loosen the nuts securing the remaining cushions.
Disconnect the wires from the differential lock indicator light switch
Place a support under the transfer case, unscrew the remaining nuts securing the cushions
Remove the transfer case.
Install the transfer case in the reverse order of removal
To disassemble and assemble the transfer case, see this article - How to repair the transfer case VAZ-2123