Islamic Republic of Iran Air Force Saeqeh (Thunderbolt) is a modified version of F-5E. It has been fitted with twin vertical stabilizers. As such, the livery adaptation in the rudder section does not 100% match to the actual plane.
To install, unzip the .rar file and copy/replace the folder either to:
~\Saved Games\DCS.openbeta\Liveries\F-5E-3
or
~\Eagle Dynamics\DCS World OpenBeta\CoreMods\aircraft\F-5E\Liveries\F-5E-3