You equip bomb then walk up to each point marked on your map. TO place them walk up to the side of the sub, then slowly walk until it gives you the option to place the bomb with your E key. Do this for each one.
Then equip the remote and as you walk to the end of the platform back onto the snow(where the 3 guards are stationed) use your fire key to activate the bombs. If you walk too far away you won't be able to activate them and too close you die.

we place it on the week spots near the sumarine.