Protract and depress your scapula, shorten your core as much as possible while squeezing your glutes inwards (posterior pelvic tilt). Aim to keep your hips level with your shoulders for perfect execution. However, keeping hips lower will put more pressure on your delts and you will be more likely to lose protraction. Hips higher will make the lever a bit shorter and put less pressure on your delts - rendering the exercise a bit easier but looking less desirable.
Tip toe and lean forward until your feet start to lift off the ground. Planche is an incredibly challenging movement so adjust height of your hips to allow yourself as long of a hold as possible. If you struggle to reach 3-5s hold in this progression, consider regressing to straddle planche, Straddle Pike Planche, One leg Planche, flying frog planche or tuck planche.