Front squats are a learning exercise, which requires a bit of time to get the correct form down.
Most BB'ers have a tight shoulder girdle, alone with triceps. The stretching of the elbows, triceps, delts and shoulder joints will adapt better the more you practice the lift of resting the bar on the finger tips and front delts. As you advance, you can cross hands or do the hands free (arms stretched outward and slighlty above.) I find no great advantage in doing them hands free, but does look somewhat cool to some people.
Start with a very light bar and try not advancing the weight too quickly at first. Want to get into the habit of the bar within and resting on the front delts/upper pec's. May seem hard for the first couple of weeks but after that, can almost seem natural in a way. May also have to adjust the grip (middle-wider) depending on body type and the elbows. Want the bar setting correctly, else this great quad exercise loses a lot of it's value. Never lean forward when doing front squats, if you do than your using bad form or the weight is getting away from you or just too heavy to begin with. You can go very low in this exercise, though not always needed. Most BB'ers do a couple of inches below the 90 degree knee break. Can do bench front squats also, a very affected leg exercise.
Best single whole body exercise would be the squat clean (going very low) and jerk-press. Try that for 8 to 12 reps of 3 sets, if only having time for one exercise. Good Luck
