Instructions
Hold down the "Circle" button to open the radial weapon selection screen. Use the left analog stick to highlight the claymore, located in the bottom right corner of the screen.
Release the "Circle" button to select the claymore. Aim the camera so you are looking at the ground. Your cross hairs turn a light blue color if you can set a claymore on the ground in that area.
Press the "R1" button to place a claymore. The detonation device takes the place of the claymore icon in your weapon selection screen.
Wait for an enemy to walk near the claymore. When you are ready, press "R1" to detonate the claymore and kill the enemy.