1. Copy and paste the rtm sample animation located on "\Steam\SteamApps\common\Arma 3 Tools\Samples_F\Test_Anims\" called "AmovPercMstpSrasWrflDnon.rtm" to "\WEAPON_FOLDER\data\anim\" where "WEAPON_FOLDER" is the weapon of the project you are doing.
2. Copy and paste the model.cfg provided on Sample model ("Samples_F\Test_Character_01") to"\WEAPON_FOLDER\data\anim\"
3. Change the handanim[] parameter to "handAnim[] = {"OFP2_ManSkeleton", "\WEAPON_FOLDER\data\Anim\AmovPercMstpSrasWrflDnon.rtm" }" on your cfgWeapons of the project.
4. Pack the addon with addon builder.
5. Check if the handanimation is displayed properly