the level 4 of this perk mentions: Your explosives now do double damage. Mines and grenades shot in V.A.T.S explode for double damage, too.

Question is how do I do this :Mines and grenades shot in V.A.T.S

I am on ps4-& rank 4 of this perk, (afaik) to load a grenade /mine, I choose it from the pip boy , then equip it pressing the right above shoulder button(think it's called the 'R1' button) and once released it releases the mine/ grenade.

I tried with VATS on ...but it did not work for me

how is this done in VATS ?...anyone ?

if you see a mine on the ground, or someone throws a grenade at you, you can target it in vats and shoot it.

but I could do that without even having this perk . what you mention is default behaviour sans the perk

the perk increases the damage of the mine or grenade that you shoot.

a..ha...!