Place feet more than shoulderwide beneath bar, squat down with back straight and grasp bar slightly shorter than shoulders. Use overhand or mixed grip. Hold lower arms between knees.
Lift bar up by completely extening knees and hips. Keep back straight throughout movement. At top of motion pull shoulders back. Return and repeat.
There are two options of letting barbell down:
1) until barbell touches floor.
2) until bar passes knees.