Bend your knees to lower down into a split squat. Your left knee should ideally form a 90-degree angle so that your thigh is parallel to the ground, and your right knee is hovering above the floor. (Quick position check: your left foot should be stepped out far enough that you can do this without letting your left knee go past your left toes—if you can't, hop your left foot out a bit farther away from the bench.)
What you can do is remove body fat from your entire body. Basically, you have to decrease your overall body fat composition if you want to lose weight from any specific place on your body. When you do that, you are going to eventually target the part of your body you want and you're going to lose body fat there. You can't just do 1000 push-ups every day and lose arm fat. Instead, you have to lose body fat in your entire body while building those arm muscles. You build up those muscles so that when your body fat percentage is low enough, they can show through.