Start from solid agar in the fridge or start from powder and follow the protocol.
If starting from solid agar in the fridge, heat in microwave (cap unscrewed) 3min on high, 5 min on 30% (till it melts completely).
Wait till cool enough so that you can touch it for a minute (60 degree Celsius).
Add appropriate volume of Kan (1000X). For 500 mL of LB Agar, add 500 uL of Kan.
Add appropriate volume of X-Gal (1000X). For 500 mL of LB Agar, add 500 uL of X-Gal. (X-Gal is solid at 4 degrees, so take it out to thaw.)
Swirl to mix, use pipette to transfer 20 mL into each plate. Avoid bubbles.
Allow plates to cool and solidify. Mark antibiotic on side of plate.
If LB Agar solidifies before being poured, microwave to liquefy again.