Begin by using a diamond grip to grab the dumbbell on one side, then lift it up behind your head, being careful not to bonk yourself. Bend your arms until your elbows are at about a 90-degree angle, then extend so your arms are fully straight. Keep the elbows tucked close to your head the entire time. You can do these with both arms or one at a time, starting with your weaker arm and matching the reps with your stronger arm.