How should I do front thigh exercises?

The best exercise to start with will be a squat:

• Squat – stand with your heels in front of something such as a bench or a chair. Next, keep your chest tall as you bend at your hips and your knees as if you were able to sit into the object you have chosen. Continue to lower yourself until your butt touches the object. Be sure not to fully sit. Following, press upward through your heels to the start. Repeat 2-3 time for 10-15 repetitions.