To get deeper into badha konasana prepare with extended stays in paschimottanasana and upavishtas konasana.
Sit up tall lifting up out of the pelvis
sit as far forward as possible on the sit bones
As you bring your feet closer towards the perineum, keep a little space between your feet to allow the turn outwards as if opening a book, turning your soles up to face you.
To allow this to happen there is a rotation in the hip joint, this should not be forced but something that will come over time as you work with hip opening postures like those in the Seated and Asymmetric particularly the janu sirsasanas.
In this version you lift up and sit on the heels holding onto the feet (there is another advanced posture where you roll your feet over so that your heels face forwards and your toes point backwards before sitting on your heels), engage Mula, Uddiyana and Jalandhara bandha
Padmasana will be looked at in more detail in Lotus subroutines
Gomukhasana has too different versions, one where you sit on the heel and the one shown here practiced in Vinyasa krama where you sit between the heels.
NB: These are practice notes that will be tidied up and put into the new edition of my Vinyasa Yoga Practice Book along with the current sequences and subroutines. The book can be freely downloaded HERE. There is a page on Facebook HERE with all the latest sheets and updates. This book is in no way a substitute for Ramaswami's Complete Book of Vinyasa Yoga.