How To Install TWRP Recovery in Redmi Note4

Without bootloader unlocking it is not possible

i got error fastboot : The term 'fastboot' is not recognized as the name of a cmdlet, function, script file, or operable program.
Check the spelling of the name, or if a path was included, verify that the path is correct and try again.
At line:1 char:1
+ fastboot devices
+ ~~~~~~~~
+ CategoryInfo : ObjectNotFound: (fastboot:String) [], CommandNotFoundException
+ FullyQualifiedErrorId : CommandNotFoundException how can i fix it?