Instructions
Select "Multiplayer" from the main menu.
Select "Create A Class."
Select "Equipment." Select the C4 from the list provided. You must be level 43 before you can use the C4. Once the C4 is selected as part of your loadout, you will start every game with it.
Use the "Equipment" button on your controller or keyboard to throw the C4.
Press the "Equipment" button again to detonate the C4 when an enemy or group of enemies runs past. You only receive one C4 per life.