3rd Person Throwing Grenade Question

Hi all! I'm currently developing on a game called Three Worlds, a 3rd Person game. Everything is all set up, the levels, player etc. Now i want to get started on weapons. I've decided to start off with the grenades. I managed to create a 'throwing grenade' animation for the character and now here's the tough bit.

Just as i click the button to throw the grenade (Left Mouse Button), the grenade appears when the character animation looks like as if he is throwing the grenade and the grenade is then thrown somewhere, like force is applied to it with the rigibody attached, and after about 3 seconds, the grenade explodes.

I've managed to create the models, the explosion particle effects but i want to know the coding for this to work. I'm not much of an experienced scripter so i'm not exactly sure what to do.