$ sudo apt-get update
$ sudo apt-get install freeradius-rest 

freeradius-rest is installed in your system.

Make ensure the freeradius-rest package were installed using the commands given below,

$ sudo dpkg-query -l | grep freeradius-rest *

You will get with freeradius-rest package name, version, architecture and description in a table

freeradius-rest package basic information: