how to make objectives

how can i make objectives in my game

like the objectives style in cod or medal of honour games

for example:

the player should plant explosives beside four tanks to complete the level

if the player plant only 3 the game is not completed

please help me

i need the method or the way that i can start

i am a unity beginer

If you are a unity begginer, you won't need to worry about objectives until your game is at least at the point where you can walk around and test the objectives.

One way to check for 4 explosives in a given location would be to put an invisible object there. Check that object for collisions and if there is a collision with a "bomb" object increment the bombCount value. Check if (bombCount == 4), then end mission.