Odin is Samsung flashing tool. Which is made only for Samsung mobile and Samsung devices. This is using for flash of Samsung devices and root on Samsung devices. 

Odin allow to you for flash stock firmware for Samsung mobile and Samsung all devices. This tool is very use full for Samsung flashing to working conditions. 

You download firmware for your Samsung device and extract the firmware. After this you got some files as AP, BL, CP, CSC and Home. You can upload all files one by one according

to their options. Click on AP and Upload file. in this way upload all files. 

Note: During Flashing, your phone must be in downloading mode. 

After all procedure click on start. and run the files. At the successful you Odin show pass and your Mobile going to restart.